[Fyron]

It would also decrease atmosphere contention with other races.

I could make domed colonies have more space like in FQM for SE4 to compensate. If I made domes impose a 70% reduction instead of 80%, it would more or less balance out. Assuming 100 medium planets, we have breathable facility space + domed space (reduced to facility count for stock 1000 kt all facility size):

20 x 10 + 80 x 2 = 360 stock 5 atm and 20% dome
10 x 10 + 90 x 3 = 370 proposed 10 atm and 30% dome