Hi! I’ve increased the seam width in the kits to 30 mm based on customer feedback, but I haven’t tried any wider than that. I think it should be fine to go wider, but only up to a point (because the tubes meet at an angle and the seam strips have to mold to them).
Also, I’m not sure if you’ve been adding seam sealer to the inside of the seams, but since I started doing that I haven’t had any leaks.
Cheers