Second black hole is an absolute beast to economy.

Stats page is previous best WITH the 1.8x trade off perk at roughly wave 1500. Current run is WITHOUT the 1.8x trade off perk and 2nd black hole started at wave 900

To anyone that just got black hole, save coins while researching black hole coin bonus and get 2nd black hole ASAP. It may slow your research progress for a week or 2, but damn it really boosts your economy.