I need to know which to use as main hand. I would think to use the mace, because it has higher dps. However, my "Damage" stays the same no matter which i use as main, and i get more attacks per second by using the fist weapon as main. So it would make sence to use the fist weapon as main... Is this correct?
The way it works is that it alternates between your weapons for combo attacks and uses your listed dps for cooldown attacks, in general. Which wpn is in your m.hand is irrelevant.
If you want to verify this, walk out of town, hit a monster once with a combo skill and look at your character sheet.
There is no tests to prove it (that Im aware of) yet but it always seem like faster MH weapon is better because in your initial 3 strikes rotation it will use faster weapon for 1st and 3rd strike thus generating spirit faster and your damage per second will stay the same.
By the way unless you have tons of LoH/LPSS on your other gear those weapons are terrible choice for a monk in higher inferno acts.