@TheOGMiyagi I can't really remember how it was exactly done, since its probably been like a year and a half, but you only need to have positive or negative karma respectively to get the job and promote. The amount of karma doesn't matter, so you can just use real/fake ids to switch karma between jobs if you want to promote one. Main focus though, is just the hitman since it has 6000, 7000. 9000 and 21000 bonuses. Also, I just remembered using three trophemon as well for quick initial cash as well, that is definitely the best way to get cash early and consistently.
I'm trying to recall, when I think I practiced my runs, since practicing with gambling is inefficient, I basically spammed stickbucks then went to gym in the morning/afternoon. Repeated it until I had enough strength for the police/hitman job, then basically ran them until I got enough money for everything, and then finished the run normally. My fastest time was around 14 or 15 minutes. But yeah I think this would be an interesting run category, and for me at least, it was wayyy more fun to play this way.