I used to kayak before I got into sailing. I was always tipping my kayak over. They are a bit unstable, but since I'm a bit unstable too, it all worked out.
Personally, even in 40 degree weather
, I'd have bare legs relying on the boat for some insulation
. I used to be an ACA kayak and canoe instructor and still teach kayaking so am happy to answer any questions anyone may have. I'm not the most knowledgeable in all the various models currently available.
One thing about boats, is they have both initial (primary) and secondary stability. How stable it feels and the tip point are not necessarily the same thing. In terms of a kayak used for a dingy, you probably want to select a boat with good primary stability.
Paddle by rotating your body, rather than trying to do it all with your arms.
Mintyspilot: I did some kayaking up near Plas Y Brenin, near Capel Curig near Betws Y Coed in Wales. Beautiful.