I have decided to use this gear for a shop light and re-configure my lamp with GU-10 bulbs.
This will cost about $25 for 5 bulbs.The GU-10 has a better heatsink too, and 500% easier to waterproof the lamp.
I consider this experiment to be a reasonable success. But the box doesn't quite fit behind the tank without fiddling, and I don't like the unsealed pucks, and with a full length lens the housing will trap heat.
I don't need more heat.