Don't know if it would fully solve the clearance issue but the Domino throttle assembly is far smaller in OD and thinner as well, along with the benefit of better response and less rotation. You could grind the locating pin off the switchgear and move it closer to the grip, then slide the lever clamp over so the bend in the lever clears everything allowing compression to the grip if you like.
I love the idea of a master with adjustable progression and bitepoint (I have masters like that on my mountain bike, believe it or not) but I am picky about lever length, position, and feel and the RCS look like they are restricted to proprietary levers only. I don't think CRG or anyone else I've looked at have lever options for them