Shop here is,or supposed to be at 50% humidity year round and temps adjusted to pi$$ off the wife(kidding)....I'm going to be comfortable.
Reloading is a spare bedroom.
From a "can have anything I want" standpoint,being as parts/labor is 99.9% done in house anyway.....air movement,which is the "V" in HVAC along with insulation is the most bang for the buck.Start looking for "dead zones" that are at a stall wrt ventilation and your system in general.The contractor can only go so far.....he's not the one using the system.No digs,just sayin...the customer bares a huge responsibility when trying to dial in a well defined,"conditioned" area.
Very best of luck with your shop,loading area.BW
Edit;look for info on usually,ceiling mounted air scrubbers.Two general methods of approach,one is center mounted the other,perimeter.The latter we call "racetrack" because we have the air circulating around the shop walls.There's filters in these....only your imagination,and some time is limiting your choices here.I build ours out of old squirrel cages,lots O filter area,wall mounted switches and timers.But have to say,the last one was surgically implanted into the unused base of a pce of equipment.It's very nice(free) because you can aim it's exhaust at a dead zone.Look on Grizzly site for specs and features.Then google'ize DIY.