You mentioned in your reply that a deck oven cannot be mastered overnight, and I am wondering what the hard parts of the learning curve are.Launching
Deck ovens tend to lose a great deal of heat when the door is open, so everything you do needs to be done quickly and efficiently. You need to be able to launch a topped skin off the peel with a quick flick of the wrist and in a fairly accurate fashion- all while keeping the toppings in place. This takes some time master.Turning
Again, since time is of the essence, you want to be able to rotate the pie and return it to the same spot pretty quickly. A home baker might lift the whole pizza to turn it, but lifting and pushing the lip is far faster. It takes a gentle hand, though, not to damage the rim or tear the undercrust. You also need to be able to develop a sense for when pizzas are both able to be turned (turn too quickly and your working with gooey dough) and ready to be turned.Hot/Cold Spot Recognition
Some ovens have less disparity in temps than others (such as Walter's old Blodgett with the original stones and a Marsal MB), but every deck oven is going to have hotter and cooler areas. Electric deck ovens have two elements- one beneath the stone and a 'broiler' element, and they usually have thermostats that can be set independently. But electric deck ovens are not the norm. Gas ovens outnumber electric by a wide margin. Gas ovens have one gas burner under the stone with one thermostat. The heat from the burner rises up/radiates to heat the stones and flows around the stones and up the side walls to heat the ceiling of the oven and bake the top of the pizza. Better gas deck ovens will incorporate some metal sheeting between the stone and burner to deflect heat away from the stone and send more up to the ceiling.
Burner shape varies. It greatly depends on the deflection, if any, and the stone material, but in many deck ovens, where the flame of the burner hits the stone, that area tends to be hotter on the top of the stone than other non-flame areas. Some manuals will give you diagrams of where the hot spots are, and while it doesn't hurt to consult the manual, an IR thermometer is indispensable for confirming hotter/cooler areas. You need to have a clear image in your mind of the temperature geography of your oven.Retrieving
Again, because of the need to minimize open door time, you'll want to develop a sense for when the pie is done, without having to check it much.Temperature Determination
Because gas ovens have bottom burners and frequently lack the necessary deflection to direct enough heat to the top of the chamber, as you turn up the thermostat, they tend to go out of balance, baking the bottom of the pizza faster than the top. Bake time is responsible, to an extent, for oven spring, though, so, for NY style, you generally want to bake the pizza as quickly as you can, so the trick is to either get an oven that's balanced at higher temps (i.e., has good deflection), add deflection, if you're in the position to, or, if you're stuck with an imbalanced oven, find the maximum temperature you can work at while still getting good top/bottom heat balance.
Quite a few of these skills overlap with a wood fired oven (which, imo, is considerably harder to master), so if by 'open flame' you mean 'wood fired oven,' then a deck oven shouldn't be that difficult for you. As far as getting a job in a local deck oven pizzeria... I wouldn't recommend it. Everything I've outlined above is for people that care about the quality of pizza they make. Your average Michigan (or, for that matter New York) pizzeria owner might work at minimizing open door time because open doors translates into higher fuel costs, but they're generally not going to care about faster bakes. Supino (Detroit) might care, but you're not getting a job there.
May I ask why you want to master a deck oven? For NY style, a home electric oven that goes to 550 and 1/2" steel plate will outperform most gas deck ovens and be far easier to work with (no hot spots, no door opening concerns, typically less turning, etc.). If you're planning on going into the business, it's better to learn on the oven you purchase, because, as I said, every oven is different.