Darren
If you ever get to 40 or 45 degrees, you are probably in serious trouble so what happens there is not really very important.
The righting moment (tendency to come back upright) between 0 and 10 or 15 degrees is probably much more important.
I paddled a TK1 for several years. Initially an old fashioned French Tourer, built in the days when a TKI could take a tent and sleeping bag, then a racing TK1, a Sabre.
I built a Night Heron about 5 years ago and halfway through the building process I noticed that it had the same beam as the Sabre and began to worry about how stable it would be.
I needn't have worried. It was about as stable and about as fast as the old French Tourer (which was state of the art in the 1960s).
It was a great deal more stable than the Sabre, but not quite as fast.
I find the NH stable enough to paddle on the ocean without being constantly nervous and stable enough to fish from on the lake.
To help you put that comment into perspective, I never fell out of the Sabre, but used to get pretty nervous in confused choppy water.
When I was about 50, I tried to learn to paddle a K1 without a lot of success. I was no faster than I was in the TK1 and could usually only manage about 1 hour before I fell out.
I am 5'11", but only 62kg and found that I wasn't heavy enough to make the NH behave as it should in crosswinds. Your weight would be just about right.
I can't help much with the Aleutesque. I would guess that its stability would be closer to your TK1.
My use is probably similar to yours. I think the NH is a bit more versatile, but that might just be because I like the look of it better. It is a very nice looking kayak.
I hope these "seat of the pants" comments are some help.