Isotherm fridge evaporator - what size?

[MondayNever]

Hey all,
I've got a 2 cubic foot top loading freezer (ice box) with a 26 year old frigoboat water-cooled unit that leaks. At that age, I don't feel the urge to chase down leaks and I am also keen to scrap the water cooling and go air cooling. So, complete new kit (compressor/evap/condensor) it is. I am going to buy Isotherm for the simple reason that West Marine carries them and I get a massive discount through a pro account. I need a flat evaporator that I can bend to fix the box and there are only two sizes that will fit:

Model 2012 - 32"x8" (256sq in) - Advertised max freezer volume: 2.0cu ft
Model 2017 - 39" x 11" (429 sq in) - Advertised max freezer volume: 3.0cu ft

Both are powered by a Danfoss BD50 compressor.

The Question: Do I pick the 2012? I am right at the borderline. Or do I just upsize to the 2017?

My only hesitance about upsizing to the 2017 is that I don't know whether unnecessary cooling capacity will result in excessive energy consumption. I don't care about the cost difference, I just want to make sure that I am selecting the most effective and power efficient unit. I have no idea how Isotherm determines their max capacities. I will call them tomorrow before ordering, but I'm expecting a non-technical canned response.

Other info that may be relevant:
- Box appears well constructed and was used as a freezer for 25 years by previous owners, but who knows how good the insulation is. I don't intend to re-insulate at this time.
- To be used in tropical waters, water temp generally 78-85*F

[Richard Kollmann]

Freezers need an evaporator that surrounds the food or at least two evaporators facing each other. Your small freezer box might be a good candidate for a Nova Kold two plate BD 50 freezer refrigeration Kit. Good energy efficiency and good price.