Location, location, location is quoted so often for a reason. When starting a small business, the wrong choice could hurt your business before you’ve even had the chance to open the doors. Take the time to really understand your customers and do everything you can to gather real world insights that will help you determine the viability of your potential new space.
Next up are the chisels, you can start with a couple of sizes and build from there. When looking at saws, for joinery a dovetail saw is a good place to start, with a choice between western style or Japanese. For precise cuts across the grain, cutting tenon shoulders, and defining the edges of a dado a carcass saw also makes a good complement to the dovetail saw.
I would definitely stick with the vapor barrier under the floor to avoid moisture from breaking up the OSB. try to build the base high enough to keep it dry and allow airflow to dry it out under there. FYI I recently repaired a neighbor's shed roof that must have been partially repaired before with plywood. The OSB was fine under the shingles, but the plywood was wrecked due to moisture. I would stick with OSB. Since you live here in NOVA, details will be a little more helpful to you. I really can't use the shed in the summer without the AC on. It gets direct sun and gets up to the 90's in there with out any air movement. I am planning on eventually lining the inside of the ceiling with that thin reflective insulation to bounce back some of the heat.
Make sure to run ground wires wrapped around all lengths of flexible exhaust hose to prevent static build up, which can spark and potentially ignite. I chose the King 1.5 HP dust collector, with a 115 volt motor, so I did not need special wiring for it. A shop vac is a must, as well, used to vacuum out machinery, and to remove dust from furniture prior to finishing. Finally, an air filtration system was installed to clear the air of tiny airborne particles. The King KAC 650 unit I installed does a nice job, has a remote control, and a programmable delay – I usually have the air cleaner run for a timed two hours when I leave the shop.