AA in the title always attract my attention :-) Seems to be a very nice project Old-Lumens, Mag with 3x neutral white xml's, 8AA in custom built holder, I'm looking forward to how it'll continue!
I was lazy. I didn’t want to cut another two of those copper rounds (blisters) and I figured I would just use the plate. I know it’s better to not use it.
I know it’s probably too late for this suggestion, but I would’ve heated up that triple MCPCB to remove the white solder mask, sanded it down a little, then you’ll have a blank aluminum plate.
Good luck with the build anyway! I always look forward to your builds