Nice job gustaf!
That PVC board/molding is virtually indistinguishable from starboard plastic, and waterproof too. It's what I was going to use had my similar project not stalled due to fitment issues.
I've been following this thread for the replacement of my unused (but working) icemaker in my 31pc. Although I also purchased the Isotherm Cruise 49 (but in the silver brushed metallic version vs. the Clean Touch because the former is .75 inches narrower than the latter), when I got it down to the boat I realized that despite my measurements it still wasn't going to fit -- by only 1/4 to 3/8 inches. Aaaarrrggghhh.
Even using the side screw proud mount option -- without using the flange (which adds 1.5" to the 15" width of the Cruise 49) -- I simply could not find a full 15" without cutting into the rounded fiberglass side trim pillars - which I was unwilling to do. If I went through all of that and the fridge still didn't fit or was aesthetically unsatisfactory, I couldn't then simply reinstall the old icemaker. Even the inner cavity sidewalls would had to have been cut out in part because of a slight bow to the left wall, as well as the back wall for adequate ventilation.
My stock icemaker is only 13-7/8" wide x 14" deep, so a 15" x 16.5" box was just not going to fit without major surgery. I knew it was going to be close from my earlier measurements, but it turned out not close enough.
And then when I realized that the 12v feed for the cabin fridge was not in any harness anywhere near the icemaker cavity, and I would also have to pull 12v up from some appropriate source to be switched with the house battery switch, I just decided to punt. And I rarely punt.
Walking back up the pier with the brand new fridge was a walk of shame - as I had not planned on being a quarter inch shy.
Clearly, the 34pc has a little extra space to work with, as I even see some room between your flange and the rounded fiberglass pillars on either side. Glad yours worked, really looks great.
PS - Understood on the need for a louvered grill underneath. I was going to re-purpose the icemaker's grill with some modifications, but if that didn't work was going to use this one after I ripped it across to be the correct height. I figured you'd never see the rip under the proud mounted fridge door.
https://www.lowes.com/pd/Accord-Ven...6-in-x-14-in-Actual-7-7-in-x-15-71-in/1095587
PSS - Just curious where you pulled 12v from for the fridge, as i see you too were replacing an AC icemaker.