I just want to add my voice to the "seat is too high" chorus. I have one of the flat Therma-Rest seat pads in a rather tender composite boat. Fully inflated it is less than 1" thick but has quite a destabilizing effect. Deflated to the point where it provides minimal (but welcome) padding, stability is much greater.

I use the fully inflated pad, or even a 2" foam cushion, for training paddles on protected water with moderate waves to improve my balance and boat control.

If your experience is limited to a much wider, more stable boat, lower your seat and get out and paddle. Build your skills, perhaps take a class or two. When you start to feel comfortable, push your limits gradually and safely.