Good luck with that project, probably because its sidewall is so stiff I've heard the BFG is a major ***** to winch up in the spare wheel well. I would leave the tire as deflated as necessary to get it up, and either live with the spare tire TPMS fault that pops up (briefly, then it extinguishes) whenever you start the car, or turn off spare tire monitoring via diagnostics - you can do that with an IIDTool. Even if you somehow figure out a way to inflate the spare after winching it up (the valve stem will be facing up), it will likely not be anywhere near the pressure it needs to be to turn off the TPMS warning, and on top of that you run the risk of the tire jamming up in the well when you really need it to drop. I've seen that happen on a trail, not fun.