: My friend is around 5'10 and a bit over 200 lbs I'd say and the boys I
: haven't seen. He was talking of around 20' or so

IMO - 20' is REALLY big for a canoe. If he wants to seat three for day paddles, 17' (probably 16') is big enough, more important is where the seats go, and that'll depend on how big the boys are. Probably easiest is to set up the canoe with the standard tandam seating, but add a center seat that can be used for a 3rd person or when paddling solo. If the center seat is adjustable fore & aft, the trim can be adjusted for the conditions and the load. This can be accomplished by having the seat suspended on rails, or just using some sort of box to sit on (my tackle box works very well). For three people on weekend trips, 18'+ should be OK if they pack reasonably well. My wife and & can fit the two of us, our large dog and enough stuff for a week very easily (with room to spare) into a 17' x 36" canoe. A larger boat will be harder to control in the wind.

Bryan