you could pull it at 190, but a brisket is not going to go from 190 to 225 in a foil tent. it might go up another 5-10 degrees at most. if you are going to leave it in your smoker for the duration, I would start checking for tenderness/doneness at 195-200 degrees. you won't need to reach an internal temp of 225 degrees for it to be done to perfection. the highest I've ever taken one is 212, and it was probably done just the same at 210. likewise, I've never had one satisfactorily tender at anything less than 203 degrees. your mileage may vary.
as soon as I'm content with the doneness, I wrap tightly in heavy duty foil, wrap in an old towel and place brisket in an empty cooler until I'm ready to eat. I would let it rest at least 20-30 minutes, but I like to have them done early, FTC (foil/towel/cooler) for up to 5 hours, so I can get everything else ready and have a couple drinks before slicing meat. it will still burn your hand after several hours in cooler. cooler works great for keeping stuff hot, too.