JAC, I was thinking of this exact thing - custom kill bag/cooler insert for my transom fish box. The one you had made by WPS looks fantastic and sounds like the service and turnaround were great. Still, $200+ bucks with exchange rate and shipping isn't cheap, though, so wanted to hear what your thoughts/review were after a full season of use - durability, cleaning/draining, effectiveness at keeping ice, etc. I currently can't keep ice for any length of time in my transom box because it's pretty much impossible to keep water out when you wash down the cutting board once you've gutted and cleaned your fish (boat companies should design this better!!).
Cheers!
Ukee