I like using one of the attenuverters on Maths for this sort of thing. Say you have both envelopes cycling/being triggered, maybe an LFO going into Ch. 2 or 3 (or both), and then use the SUM, OR and INV outs. Changing one of the attenuverters can have drastic effects on three (or more, if you use the unity outs too) parameters in nicely interrelated ways. I generally send it to destinations which change the timbre, or to play around with effect parameters.
Cold Mac is my favourite for this technique, as you said, but you can get similar results, albeit with fewer outputs, from Maths. It doesn't give you the satisfaction of turning one large(r) knob, though... it's just a small attenuverter. It's also good with other modules that have cascaded outputs so you can mix various mod sources. I use Blinds in a similar way.