Steve, first let me say that 30 years ago I had a scout master that was brave enough to do this. I built 2 kayaks (one 14' and one 16') and used them for years on rivers and lakes. I worked as a commercial guide from age 17 through graduate school and had well over 10,000 miles on rivers. I owe a lot to that Scout Master and I think you are doing a great thing. Second my experience is that often in our rush to wow scouts we permit them to exploit outdoor experiences without gaining respect and appreciation for the outdoors or the sport. Clearly building the boats will slow down the pace and improve the growth experience. Our boats were the same basic design and about 25-27 inches wide. Our seats were about 2-3 inches above the bottom of the boat making a slightly higher center of gravity. They were plenty stable even for the smaller kids. For the cost you will not find a better way to introduce the scouts to kayaking. You may want to combine it with a fifty miler this summer as a reward.