Yes; as George P said, measuring all of those factors combine for a proper fit. Proper fit is the key to shooting well with a shotgun. Can a person 'form themselves to the gun'? Yes. I did it for many years, and shot very well that way. But you're fighting all kinds of things going against you like cheek slap, uncomfortable neck positions, (the OP has already mentioned this) the gun barrel covering rising targets, and taking a beating from recoil when you don't have to. Finding a stockfitter that will take you out with a gun that has a trystock and finding how you are most comfortable and confident when shooting will do wonders for one's shooting ability. The next best thing is installing or having installed the adjustable parts I linked to in post #15, and experimenting with them yourself until you find what works best for you. (Or buying a gun that has those things on them already, which is what I did.) The Beartooth kit is a great way to start, and for the casual shooter, can be a solution.
Some things to consider:
Adding LOP will reduce the amount of comb height needed, but if your cheek is not touching the stock (and from what I understand from the OP in post #18, the stock
already has a Monte Carlo profile) you may need more height than the Beartooth kit can provide.
There is one solution for comb height that is not overly expensive; Magpul makes a stock the has adjustable LOP and comb height, though the LOP might still be short for the OP.
https://www.midwayusa.com/product/2319512418
and
https://www.midwayusa.com/product/2319258794
It goes back to 14.5", which as George P. say he can shoulder well, and he is @ the OP's size. Midway is out right now, but it should be available other places also.
I almost bought one of these for my 870 for Trap, but bought an 1100 Competition Synthetic instead.