It seems to me that the cylindrical tank might be a better shape as it would take less fuel volume to keep the klunk submerged making the most of a given amount of fuel. Anyway, I've run into this problem before while building a 40 size Stinger and hate to take any structure from F2. So I checked around for narrower dimensions and found the Hayes and Sullivan tanks to work for me. Oh yeah, I have a few extra Dubros because of it too. I'm sure I'll find a use for them someday.