I'm also using a Mac and CloneKeys and am pretty new to multi-boxing. What I did was use WASD and arrow keys on Main for movement. Then on the slaves, I unbound WASD and QE (strafe keys on Main) and kept arrow keys. CloneKeys isn't perfect and it would be nice to have "Don't transmit" options but its pretty much the only key clone program for the Mac so it is all we've got. I figure it's better to (slightly) adjust how I play rather than to fight a program I can't change.

Maybe we (Mac users) could submit some suggestions to the author of CloneKeys to get some options put in?