Question about pinion length and setup bearings.

Im regearing my d30/8.25 in my 00 limited XJ. The dana 30 is stock, came on my 00', and the 8.25 is swapped from a 98 classic.
Anyways, Ive been reading about gears for the 30, and some people are talking about short or long pinions used on late model tj/xj 30's.
This is confusing to me for two reasons:
1. I was under the assumption that all TJ 30's were high pinion and XJ 30's were low pinion, so how would the tj/xj 30's use the same (short or long)pinion gear?
2. is there a way to check my pinion to see which style i need to order?

Also, is there a place to order setup bearings for either one of my axles, or will i have to make them from my old bearings?

thanks for the help.

in 2000 Jeep went to the low pinion Dana 30 TJ pinion for all the XJs. High pinion or low pinion, the length stayed the same. It sure made it harder to raise the XJ and make the pinion angles work.