As far as glass boats go, you can't beat a Lavro. Ron builds each boat himself, by hand. Each layer is laid with sheet fabric then hand painted with fiberglass, layer after layer after layer etc. Most of the other bigger glass boats builders just blow the glass mixed with fabric pieces into a mold in one shot. As for the balance difference between running with friends aboard or by yourself, just get a boat with adjustable rowing seat and oarlocks.

Beezer