Around how much power do I need to clear the ?-4 and ?-8 levels? The other 6 levels are very easy to clear but there's a sudden bump in pest power on the ?-4 stage, I wiped on the first mob I think. I haven't tried ?-8 yet but I'm assuming it's as difficult as ?-4 so I don't want to waste stamina on it if I have no chance of clearing it.

My squads have 54048, 34322, 35107 and 26718 total power. At what point should I attempt the ?-4 & ?-8 maps?