Vans standard is countersink thickness above .040". Dimple .040" and less. Usually a dimple is stronger. Sorry, not building a 10 so I don't know the parts. My guess would be countersink the bracket and dimple the skin.
Estes Park, CO
wirejock at yahoo dot com
Donated 12/01/2017. Plus a little extra.
RV-7A #73391, N511RV reserved (1,800+ hours)
HS SB, empennage, tanks, wings, fuse, working finishing kit
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.