Are you using live culture from the fridge, or you using dry culture then using it?
Reason I ask, when I followed the recipe, the dough was very dry, too dry to get it to form a ball in the mixer. I had to add maybe a tablespoon of water to get it to form a ball, so I do not know where the hydration is at, kneading is off from your recipe being I was not able to get it to ball. Used my Italian 00 flour, might have to go back to lesser expensive flour until I get this figured out. Although, the different flours behave differently.
My oven is not near what you use, I have a baker pride counter model. Still learning on how to get the most out of it.
The culture is wet, and most importantly, fully active. I time the feeding so that the activity peaks right about when I need it. It doesnít have to be perfect, but the closer you get to the same level of activity each time, the more predictable your results.
If you followed my recipe, your dough should be relatively soft and still a little tacky after your initial mixing. You should have no problem forming a ball regardless of what flour you use. For your oven, you may get better results with malted AP flour such as KAAP than an unmalted 00. What sort of mixer are you using? It might be difficult to make a dough in a stand mixer with only 275g of flour. If you are only going to use 275g flour, your best bet may be to simply mix by hand. A food processor would also work, but I canít give you any guidance on that other than to be sure you donít overdo it.
For 275g flour and 2% culture as you noted, you would, dissolve 8.3g salt (3%) in 171.9g water (62.5%). Then dissolve in 5.5g (2%) culture. To that, you would mix in your 275g flour. Your total formula would yield 461g of dough.