I like to have a firm but not tight/scrunched down cheek poisition and when I open my eyes I like to see to barrel just the front sight and the breech llug top. If I do not have this I try to work on the stock to get it or closer to it, a longer LOP than normal can help with some stock profiles, one can have a very good smoothbore fit if building the gun them selves and work the stock/comb while shooting the gun,you can use a portable workbench with v blocks and rasps and scrapers removing wood in between shots and using pellet stove ash, camo cream or something similar to put on your face to transfer the "cheek"/face to show where it lays on the wood and work off wood where the ash shows,you can duplicate this on the other side to maintain asthetics, most pre-carves have plenty of wood to work with,front sight placement can be determined at this time also, sometimes it does not take a whole lot of wood removal to get the fit I think that due to neck and face feature difference many folks struggle with some typs of guns and oher have no problems with the same styl., It might do one well to try a few different types to see what fits the best out of the box so to speak. The addition of a rear sight can also help if one has to scrunch down, it alows one to shoot with the head raised up to align the sights.lots of things to try and if you find the right mix a smoothbore can be very accurate out to 50-75 yds without getting smacked when shooting it.If you are lucky enough to lay your cheek on the stock with a little pressure and open your eyes and have the sight picture wanted the gun may be right on for you and not hurt a bit I have had a couple like this. one may need to bend the barrel for windage and elevation which is common. a combination of wood removal and barrel bending may be needed in some cases I would think. Some of the real gun builders here probably have a better take on this topic than this old novice gunstocker.