Nick has the experience here, and as you know he recommends a square edge due to the abuse during the building. I am past that point with my Guillemot and I would have to agree with him. Just the simple process of trimming the extra glass after glassing the inside and outside would probably destroy most of the cove edges unless you were really extra careful. Also at the ends, the joint really is at a great angle and the cove would probably hinder the two strips making proper contact.