He is not trying to seat the rings, they are stuck in the ring lands. Heating and cooling cycles and low loads are the best chance of loosening then up.
Putting a load on it is a sure way to burn through the rings.
X2
Time to do a ring clean as well. Several ways to soak cylinder / rings but general instruction is to pour liquid cleaner into plug hole & soak for instructed time then expel from cylinders (can make mess if not thinking!). The old G.M. Top Engnie Cleaner was great (in metal can), new (plastic jug) stuff is weak. Even diesel fuel will do some good. Engine at operating temp is best, some of this cleaner is going into the oil so drain & refill. It will smoke like a pig, nice if you not in town. With some time it love it might come around! If compression doesn't improve might try to find someone with a borescope to have a look inside the cylinder.
P.S. Dave & retired wrench must have been raised rual too, teach 'em to lead!
