Are you still planning to try them both (180 gen. II and 220) side by side underwater, which will be the real comparison? Curious to see how that works, as I've got 2 180 gen IIs (and a soft Goodman handle) on the way from Piranha. For that price, I can afford a slightly less than optimum result, and I expect they will be quite a step up from the Impact XL or Mini Q40 eLED Plus which I currently use for day time diving (and even night, if I'm with someone with a more powerful light).
I needed a couple of GUE-compliant backup lights for Fundies in any case, so these were a cheap solution, even if I'd prefer AAs or CR123s instead of AAAs. And if worst comes to worst, after Fundies I can always give them away as presents, keep them as loaners or just add them to my lights drawer.
Guy