Cool project! That XT will make a great all-around explorin' machine!
I've sure enjoyed my XT225 and have no intention of ever getting rid of it, it works well in so many situations... Upgrading the front and rear springs (36mm front forks on both the 225/350) was arguably the best bang-for-buck upgrade I've done on mine as well. It's been the perfect bike for bombing around the GP and riding every which way back and forth over the passes.
The Tusk panniers look really nice , can't wait to see the rack your gonna fab up for them!
"Remember, you may have to grow old, but you don't have to mature." - Red Green