i built my DDRM v2 in 09/2019 (after 5 rev1. builds)
BOM
make sure you have an 6N139 instead of 6N138 in the output board or you run in an issue with stocking notes
Soldercore:
use no clean solder core, (do not use organic based flux based core)
...
use no clean solder core, (do not use organic based flux based core)
...