ya same here too, if anything i could come help ya when you need to put the 8.8 together. im a whopin 2 blocks away and as you know have already done it befor
not sure on driveshaft length (rumor has it that the 8.8 pinion length is similar to a d35 but I'm not sure, verify this) but you won't need any shims if you do it right, sit the rearend on jackstands, toss the ubolts on loosely with the perches in between, bolt up the driveshaft, raise pinion till the angle is right then tack the perches and remove it from the vehicle again to weld it fully. Voila, perfect pinion angle with no shims.