Is there any reference to ballpark how much total bonus that I need to unlock the next girls?

Right now I have 300 x 64 == 19k total bonus, which is enough to get Pantress after a few hours of mostly fake-its, but I figure that I need an additional (x60) to get to the same level with Victoria (maybe more). I can't get that with resets alone and I'm 150 gems away from my next (x8).

What's my best play? Waiting a month to unlock Victoria for those 20 gems (and any bonus gems for completing 9 girls ina future event) or just grinding out resets while earning 6 -10 gems a week from battles until I get the next (x8)?