I suspected you were using an Italian flour like the 00 flour because I use such flours a lot and have come to recognize the crusts made with them. There is nothing wrong with using 00 flour. It's just that they are a bit tricky to use. Italian flours like the 00 are milled differently than the flours in the U.S., they are graded differently, and can have widely varying protein content from brand to brand and even within the same grade. For example, the Delverde 00 flour has 9% protein while the Caputo 00 flour has 11.5-12.5%. The King Arthur "clone" of the 00 flour has 8.5% protein. Your 00 flour (Molini Pizzuti) has 9.5%. My favorite is the Bel Aria brand, but I have yet to be able to figure out or find out how much protein it has (I'm guessing around 9 percent). I have been told that the most common 00 flours used in Italy are the Caputo 00 and 0 flours, and are considered the Cadillac of 00 flours. They are available in the U.S. but only in 25 kilo bags. I have yet to try the Caputo flours but recently was given samples of the Caputo 00 and 0 flours by the chief pizza maker at Naples 45, a NYC restaurant that specializes in Neapolitan style pizzas, and one of the two NYC pizza establishments (at the moment) that carry the certification of the Associazone Verace Pizza Napoletana (VPN) because of the authenticity of Naples 45's Neapolitan pizzas.
I mention all of the above because your results can differ quite a bit from brand to brand, and also in the manner in which the dough is prepared. The classic Neapolitan 00 pizza does not use any added sugar or olive oil, even to oil the ball of dough (although I generally do). And the dough is kneaded for long periods (up to 30 minutes) and subjected to long rise times, sometimes up to 6 hours (e.g., either a single 6 hour rise, or a 4 hour rise followed by a 2 hour rise). In the absence of the use of sugar or oil in the dough, and because of the relatively low protein content of 00 flour, the crust will usually be very light in color, like the one in your photo. The chief pizza maker at Naples 45 once told me that even he adds a little bit of sugar to the 00 pizzas he makes at home because his relatives aren't used to seeing tan or almost white colored crusts. Adding a bit of sugar and olive oil to your dough will produce increased browning.
I think the unfavorable results you achieved recently may have been as a result of the way you managed your dough. Dough is relatively forgiving, but it can't tolerate abuse by putting it in and out of the refrigerator several times. I suspect the dough ran out of food (sugar) and that was the reason it was slack and the crust remained almost white no matter how long you tried to bake it to get it to brown up. I once made a dough using a blend of flours that was supposed to mimic the 00 flour. The instructions were to let the dough rise for about 24 hours on the kitchen counter. I scratched my head about this because I didn't think the dough could last that long without overfermenting, but I followed the instructions anyway. The results were a disaster, and the crust came out just like yours. The dough had run out of steam because of the overfermentation and was very slack, soft, and overly stretchy.
My best advice if you plan to make 00 pizzas is to find the best brand for your purposes and tastes, and use a recipe that best makes use of the brand of 00 flour you select. I have set forth below a recipe that I understand is a classic Neapolitan style 00 dough recipe as adapted for American home use. You may want to try the recipe out using your brand of 00 flour and see what happens. With experience you should be able to get the results you are trying to achieve. In the meantime, I would take a hard look at the recipe you are now using. If you have been getting consistently poor results, and assuming your oven is not at fault, then it is quite possible that your recipe is flawed or that the 00 flour you are using is not the best one for your recipe. I found this to be the case when I first started using the Delverde 00 flour and the King Arthur clone of the 00 flour. It took me a long time and a lot of experimenting to figure out how to use them most effectively. Now I just stick with the Bel Aria brand of 00 flour because it seems to work best for me.
As for the amount of IDY you are using, it seems to be OK in relation to the amount of flour you are using. In the recipe below, the yeast called for is either cake yeast (which is what is used in Italy) or ADY. You can make the necessary conversion to IDY without any problem, and simply mix the IDY with the flour. The recipe also calls for kneading using a stand mixer, but the dough can be kneaded by hand without any problem (and for a shorter overall time than called for in the recipe). For now, I would hold off on using the milk powder, at least until you figure out why your doughs haven't been working out.
Home Version of the Authentic Neapolitan Pizza Dough Recipe Using "00" Flour
1 1/2 c. warm water (80-90 degrees F for cake yeast or 105-115 degrees F for active dry yeast)
1/2 (0.6 oz.) compressed cake yeast or 1 t. active dry yeast (about half of a 1/4-oz. packet)
4 c. "00"; flour (Farina Tipo 00), Bel Aria brand preferred
1 T. sea salt
Olive oil, for the bowl (optional)
Combine the water and yeast in a small bowl and proof until foamy, around 5-8 minutes. Put the yeast mixture in the bowl of a heavy-duty stand mixer fitted with a dough hook. Combine the flour and salt and add gradually to the yeast mixture in the mixer bowl. The dough ingredients should be kneaded at low speed, for about 10 minutes, to prevent any overheating of the dough and inhibiting the action of the yeast. Continue kneading for an additional 20 minutes. Shape the dough into a round, place in a very lightly oiled bowl, and turn to coat. Cover the bowl with plastic wrap and let the dough rise for 4 hours in a warm place. Punch the dough down, divide into 4 pieces, and shape into balls (called pagnotte by the Italians). Brush the dough balls lightly with oil, cover completely with plastic wrap, and let rise for another 2-4 hours. Shape each of the dough balls into a pizza round by pressing your fingertips into the dough so that the dough spreads outwardly, leaving the edges puffy to create a rim, or cornice (il cornicione). Grasp the rim with your hands, working your way around the circle. As the dough dangles, it stretches by the force of gravity while the edge stays plump. When the desired diameter of the pizza round has been achieved, place the pizza round on a pizza peel that has been dusted with flour or cornmeal. Finish by topping with pizza ingredients of the highest quality and bake on a pizza stone that has been preheated for 1 hour at the highest oven temperature possible (usually 500-550 degrees F for a home oven).