the 3/4 rule is quite widely known - and mentioned in a lot of newbie threads - 90% of the one's I've seen anyway!
probably not documented in manuals as they expect you to have done your research!!
the rule also applies to all rails - I think you may still have issues with the -ve rail - so don't be overly surprised if the uZeus craps out even with the more powerful brick - make sure you've set the jumper to the higher power on the -ve rail - but iirc the max draw on that is 500mA which you are really very close to already!
"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia
Utility modules are the dull polish that makes the shiny modules actually shine!!!
sound sources < sound modifiers < modulation sources < utilities