Can't really help on the supply front but I do have a couple of observations.
I have one so called Turners smock of reasonable fabric quality purchased many years ago at a show, thought it was on the dear side at the time, has worn well BUT it has a robust and exposed Metal Zip down the front that is a real pain if you forget and pick up that finished or part finished item to give a quick buff or sand, many's the time I've had to refinish because of the carless scratch imparted by the zip when holding the item against me.
I got my daughter to make me one with a placket covering the front zip and it saves the frustrating risk.
So beware, try to find one without an exposed zip.
As for the rear pockets, personally I very rarely use them, they still collect shavings and dust regardless and buffing cloths etc. placed in them get contaminated and few turning aids lend themselves to pocket storage.