The other thing you can do, which takes allot more time and energy:
if you can be online every 20 minutes, then you could put all energy in all your buildings, then ranked challenge and get 1/3 of your total income per houre. (then change energy back to before) this way you could also go half the amount of months to reach a girl.
And personally, i also thought to go to 200MIL (i think it was in a previous post like 40 pages ago i saw you say that 200mil is acceptable for the last girls) but i will probably keep on going because in the long run the higher your speed the faster you achieve stuff. (and i don't like waiting)
i'm at 184 now and in a couple of hours i'll be 190mil.
getting close