I was going to use scupper holes to mount but heard a lot of story's of the seams cracking from the pressure. Any recommendations on that. This was my first attempt at it.Sweet! Only thing I'd add is that you may want to disperse the weight off of those seat "feat". That much weight on just four small contact points will probably catch up to you in the form of a crack or wear point.
I like the ingenuity though!