You need to consult with a tax pro about the renting the shop from yourself thing. You may need to incorporate to do that. Also, there could be zoning issues. You may need to split off the part of the property the shop sits on. Depending on zoning that may or may not be possible. As far as licensing, 07 Manufacture or 01 Dealer. Both have their plus and minuses. Depends on what you plan to do, work with customer supplied serial numbered 'parts', or have the business buy serial numbered 'parts', build a firearm and sell it. State laws vary , so LLC may be an option for you. Setting up a Corp or LLC you can do yourself, without the need of a lawyer. But, you need a lawyer to explain the pluses/minus of each in your state. Other than that, it's timely and accurate record keeping like any other business. ATFE regs aren't difficult, but I am surprised how many can't seem to follow them.