Welcome aboard, there's a couple treads where guys have made their own splashwell buy having one the size that came in them wouldn't allow for a tiller unless the handle was several; feet long. :D
I'd normally shy away from using blinds on the bottom of the hull but if the holes are under the rib ends, you'd have to pull up the ribs to be able to buck the solids just to plug the holes. If that's a the case then I'd get some stainless steel blinds, coat with 5200 and call it good. AL...
Take care, that's a rough disease to contend with. My friends have gone with Yamaha motors and for sure a 70, anything less and you'll be wanting more.
Just like a tent during the day, it gets hot inside but at night after the sun goes down you can peacefully slumber at probably less than ambient temps due to the cool water under the hull.
