The more I looked at the countersunk holes, the more I didn't like them. The battery tray bottom is 1/16" thick sheet and the #10-32, 100-degree countersunk screws make a very wide hole, wider than the 3/16" screw diameter. I wanted more meat under those 6 screws holding my battery down back there, so I decided I would add another 1/16" spacer/doubler below the battery tray.
I will say that the designers spec'd it as is without the doubler, and there are likely 1,000+ flying without it, but to me, I wanted to add it - so I did.
I didn't count primer drying time, but I did count prepping and priming time as well as riveting and install time. It didn't help that I had to build 2 versions - but that's what it takes to make it acceptable and to be able to move on. So there you go.
version 1 - not acceptible
v2 - see the difference in front holes vs. back holes
tray installed - you can see the doublers on the front side of the tray
