We had used a cooler at first, but, like you, found it too large as well as prone to catch wind.

We added insulation to the front hatch bin and the hatch cover -- using reflextix/foam. This has worked well for our needs -- holding ice for a day's fishing and keeping the deck clear. When we keep fish, we do so to eat them, and so keep smaller fish, which fit into the hatch. We also gill/bleed the fish before placing them in the ice.

Another option we use on our tandem island is using hot/cold mylar grocery bags. We line a mylar bag with closed cell foam (fold a piece of foam in half); then place another mylar bag inside that (with the foam, as sandwich between). This has proven to be an inexpensive method that has kept ice even overnight. The larger mylar bags are a few dollars and are large enough for nearly all the fish we keep. These bags fit inside the front hatch, so again, keeps the deck clear (and out of the sun). They also make it easy to carry to the fish cleaning area.

I have an Engel 35 in the rear of the boat and am happy with that. Note: a Yeti 45 is 38 quarts and made in the Philippines and the Engel is American made and 3 quarts smaller than a Yeti 45. If that kind of thing matters to you.

In the cooler weather and to bleed the keepers I like the hoop style stringers: https://www.austinkayak.com/Large-Stain ... 9597P.html