Finally to Grandmaster.

WetHam

I finally made it through most of act 6 and all that’s left is GM. Who should I use so I don’t have to spend every unit I have?

OldManHop

I used corvus w/ white mags prefight for most of the fight and kitty pryde with Emma synergy for last phase. Your mileage may vary.

I found this video particularly useful... Just watching was way more helpful than any other guide I've seen: https://youtu.be/a9vDO_a86ak?si=AdlOiJdfCOHWwVFl