Paint Booth

Wall off a booth area. Clear plastic and 1x wood works great. Cut a couple holes in the "interior" non -door end and tape in some furnace filters. Run plenty of fans in the door. Negative pressure will keep the fumes away from your ignition source. Get the booth clean, the car masked and cleaned, heat up the space, turn on the fans, and spray. Leave the heat and fans on the whole time, including the first 3-4 hours of curing. You won't blow up. You just need fans to pull air from the booth, a way for air to enter the booth, and enough heated air volume to keep the temps where the reducer you're using will work. Also wear a good respirator.