Welcome to the Forum! You've got a remarkably handsome model under way.
Regarding those Heller kits - quite a few years ago I bought the Pamir. I never got around to building it, but I remember it as a basically sound kit. I do recall one peculiar goof in it - the sort of thing that was typical of Heller kits in those days. The designers made an effort to represent the eyebolts through which the jackstays on the yards run. Molding the eyebolts to scale was impracticable, so they put little blocks, with steps on them, in the places on the yards where the eyebolts were supposed to be. The modeler was supposed to cut pieces of wire to represent the jackstays themselves, and glue the wires to the blocks. Nifty idea - except for one problem: they put the blocks on the fronts of the yards instead of the tops. A yard with a jackstay on its front would look ridiculous. (Actually ships like this generally had double jackstays - one on top of the yard for the sailors to hang onto, and one at a 45-degree angle in front of it for the robands and other lines.) The problem, fortunately, is easy to solve. Shave off the little blocks, and figure out for yourself how to represent the jackstays - if at all.
The thing that discouraged me from tackling that kit was the scale. A ship like that had a great deal of interesting - and crucial - deck equipment, such as Jarvis brace winches. That sort of thing is awfully hard to reproduce on such a small scale. Heller made a valiant attempt at it, but those little plastic parts, to my eye, just don't look much like Jarvis brace winches.
To my recollection, though, it's basically a good, reasonably accurate kit. I haven't seen the others you mentioned, but I think they were designed by the same people at about the same time.
Another one you might want to think about is the Gorch Fock. I bought that one some years ago too. She's a three-masted barque, so she doesn't have as much rigging - and her deck equipment is a good bit simpler. She's also an uncommonly handsome ship. I'm not sure whether the Heller kit is still available, but it's currently being sold under the label of Revell Germany.
Good luck. It's a great hobby.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.