I agree, start at 25 yards, off the bench, double rested. I like to work oup loads starting with a likely good patch ball combo. Then increase the charge with each group. Say, 60, 65, 70, and 75. I often see the groups string up and down with the low charges, then tighten, then blow out larger when the optimal charge is exceeded. After that charge is pinopinted mess with patches, lubes and ball sizes.
Sighting in, see my sketch. I used to measure, or guess. Now I move the sights base on the center of the group relative to the sights. IF it were possible to put the rifle in an immobile vice, you could sight in with one group. You could fire the group then modify/ move the sights to point to the group without moving the rifle. That is not possible with this kind of rifle.
I now move the sights as best I can based on the sight picture. In the picture the sight need to be moved side-side a little over one front sight width. It was shooting low so the front sight gets filed lower to raise the point of impact. I am pretty sure the front sights supplied are made to be a little tall so they can be filed. Getting a new rear sight is the hard way.