I agree with the comments about the stock 800 seat's lack of comfort after about the first 20 minutes of riding.
For some years now, I've been using a wooden bead seat cover, first on a WeeStrom, then on a Multistrada and now on the 800 Tiger. No more butt fatigue on 500 mile days. Best ~$40 I ever spent.
I got mine from White Horse Gear: http://www.whitehorsegear.com/wooden-bead-seat-covers