I knew this raid I wanted consistency as I also underman but did not want to waste too much time. I only underman the R9 tier (GMT and scorch usually 1-2 attempts) and (JMMW, DB and TG usually 2-3) attempts. Without the R9 modifier for JV it’s not consistent any lower to underman, I run KB, JN, Plo, AS and Shaak with 3-5 attempts at R8. I do not regret filling in a few more R8 to save time. The more units the less runs.
I am also interested what makes you think your mid game, by 9M I considered myself in the end game. In that my raid performance could exceed a larger roster as the raid is focused development.