You aim at the same point of aim, basicaly whether uphill or downhill. The issue is basicaly horizontal distance. So 144 yards uphill at 45 degrees is only 100 yards along the ground, and you would use your 100 yd pin, if you had one.

A 45 deg shot uphill will almost always screw up some other aspect of your form, and so you may loose velocity or not find yourself shooting through the peep square, or a bunch of things.

Finding the base of the triangle is usualy easy in a forest, for instance if a deer is standing next to a tree you can look at that tree at the same level you are on a stand, or a hillside, and take that straight distance. It isn' t as easy always on a bare hillside.

I had a nopeep for a while a few years ago, I understand how they help with hand torque, or at least reveal it, but what do they do to improve uphill downhill. It might help with peep not centered, though not necesarily since basicaly the NP just aligns the riser, not the string, so the back of your arrow could be anywhere.