How to Trigger a Macro by Chording Two Mouse Buttons?

I'm aware of Dan's multipress macro and used his keypress counting method as part of this.

Can you just clarify how you set the trigger to be a modifier? I'm not by my mac at the moment so can't check your examples, but I must be missing something as single modifiers cannot be used (as far as I'm aware) as hotkey triggers. I don't think it's a good idea either, but that's beside the point.