I've had the leather to re trim my front seats laying around in their vacuum packed bag for a couple of months. Tonight I opened them up.
The leather is cold and pretty stiff to work with. I brought the passenger seat inside the house tonight, and am just 'placing' the leather on it so that it can sort of warm up. After it's good and warm, and there's daylight, I will start stretching and attaching it to the frame.
