Sit as low as you want. I'm suggesting that you don't HAVE to if you don't want to. The lower you sit, the longer paddle you'll need unless you're a LOT taller than 6' or very broad shoulders. The way we learn is trying new things and seeing how they work out. If you aren't going to risk more money than you can afford to try it out, I encourage you to go ahead with your plans. It may work beautifully, but if it doesn't you'll still learn a lot that you can apply to your final design.
That said, sitting with legs out in front of you is a kayak position. So, if you're going to sit with your legs out in front of you instead of bent like sitting in a chair, or kneeling as a whitewater canoeist, then I'd suspect that foot pegs would provide the same sort of advantage that they do in a kayak. So give it a try.
One way to give it a try without sinking much cost may be to a beach chair or a temporary sling seat in your canoe. For feet, in my old rowing canoe, I strapped a closet rod between the seat supports for the seat in front of the rowing seat. That allowed me to either prop my feet against the bar for more push power, or to tuck my toes under it for more pull power. It worked great. The feet are very important to rowing or paddling.
Please keep us informed of your project. These things are a lot of fun, and we learn a great deal from doing them. Pictures would be appreciated.
- Big D