I work for a large lock company (ASSA ABLOY), and suggest you not use a direct pull mag lock as illustrated above. If you are determined on using a mag lock, use a shear type mag lock where the armature has small (anti) shear pins
12' wide, and almost 11' clear under the lights. The roll-up doors on the ends are 12'wX14'h, the roll-up under the lean-to is 10'wX8'h. 16'2" clear ceiling height in the main shop. Gable end doors are offset to permit a 2-post to be in the back corner.
5/12 main roof; 3/12 lean-to roof
Try a little 100LL Avgas on the oil spot - use a paper towel to keep it wet for a few minutes and use a broom - when it dries the oil spot will be 95% gone. Obviously, be damn careful with the Avgas and flammability!!
Don't bother trying this with unleaded car gas - won't do anything
Probably not much operationally with proper air movement. I have one 220V 14' diameter BigAss Essence variable speed fan that moves a lot of air downwards in the 40x60x16 shop. The single propane forced air heater is in the corner behind the photographer.
SPOA-10 with trio arms and both round and truck adaptors. Lift 3/4 ton crew cab pick-ups, a couple of BMW's, an Austin Healey, a S550 Bullitt Mustang, a Polaris Ranger XP1000 and a 62 'vette without difficulty