Find your middle distance, so from 20 -100 yards it would average to 60 yards.

Sight for 60 yards and either print you shots near and far or work out the trajectory on a PC.

The other option is to find, using your ammo what your maximum point blank range is for you distance of 20-100 yards. I would say your point blank target area would be about 4 inches so plus or minus 2 inches. SO whatever zero that will keep it plus or minus two inches between 20-100 yards is where you will want to be.

All the technique on how many shots and how to clean it and all of that is nice but means nothing to the trajecoty and the actual practical accuracy of your rifle.