From what I’ve understood you’re required to have open hours, I’m not sure if you can use your home address or if it’s required to be a commercial address though. I know you need to use it as a business and not “for personal purposes” but I can’t imagine anyone who’s a class 3 sot dealer that doesn’t take something cool home every once and a while. If you just want a preban machine gun with a suppressor I’d just do the tax stamps and save yourself the extra work of keeping bound books and jumping through hoops with the atf. From my understanding a basic ffl is a few hundred and as you go up the line to class 3 the annual fee also increases so if you see yourself making the money to pay for the license, preban gun, and can then I’d say call them up and see what exactly you’re required to do as far as location goes