Congratulations H... She's a beauty. A Beta35 will be great. I have the Kubota 18hp and quite frankly a bit larger thrust would be sweet. Beta is a marinized Kubota, except the hp changes. If I understood correctly the Kubota18 is the Beta20.
I believe she is an ideal boat.
One thing I did was build a platform under the forward bunk. It extends from the inner hull across the boat. There is a 1.5" wide ledge on both port and starboard. Between port and starboard I placed an L-bracket to support the wood shelf I installed. It is not bolted in.
The shelf itself holds that in place. There is sacrificial rubber at the edge so the metal does not damage my hull. Then, along the front I through bolted an aluminum L-bracket, again using a sacrificial foam barrier so the metal would not damage the boat.
Heading fore and aft I bolted two pieces of flat aluminum to wedge everything in place and support the shelf.
Not pretty, during construction:
The L-brackets and those two bars hold the wood shelf. I should have used 3/8" starboard. The platform has four boards that come up. That way I can access the thru hulls.
This is being redone shortly using starboard. I'm replacing the hose and "while I'm at it" (some of the most expensive words on the planet!) I might as well replace that icky wood.
I had one 3/4" thru-hull installed to port for the eventual watermaker. Shower supply/shut off is under the sink in the head.
Good luck and have fun. I love my Seaweed. Happy cruising...