Running game in another Directory.

[OrbTweaks]

I am attempting to run your client outside of .minecraft, this is a feature in the normal Launcher. Default location is %appdata%/.minecraft I am looking it to run it out of a custom directory Ex. C:\Users\Drew\Documents\Skyblock

What arguments would I add, or what would I change to do so.

[3arthqu4ke]

Try around

hmc.mcdir=C:/Users/Drew/Documents/Skyblock

and/or

hmc.gamedir=C:/Users/Drew/Documents/Skyblock

Inside your HeadlessMC/config.properties. I advice against using backslashes inside that file, or else you have to escape them.