I hit a guy with over 200 successful BRs/ABs on Express and it didn't even take him down haha. Every time I went to do another batch, since he'd played I guess, it would start back over at 30 buildings per hit or whatever, and stay there for another 30 hits before ramping up.

edit: I guess my suggestion/comment would be in solo games, turning someone into a parking lot is too hard. I did over 200 hits! Can I recommend easing these changes off a bit in terms of buildings killed, even if you leave the civ killed formula as is?