jeremy. glad to have you back on the board- i heard you had joined a cult and spent your days sitting in a dark room chanting 'shimmmms', 'shimmms':)
the rm midvalve has been a bit of a journey for me- i was locked into the idea about using more midvalve etc, etc. i went with some taller posts and went with a more tapered stack with about 6-7 shims if i remember and a more classical 10 or 11mm clamp 8mm id shim thats floated. No matter what i did with the passive, the forks were always harsh. in the end, i went back to essentially the stock midvlave and got the forks working real nice with just passive mods. its interesting that the back plate on the rm midvalve measures at ~11.5mm, so if you think of that as the "clamp" shim i suppose you would think of the stack as being stiff, but, since there are only 4 big shims, i think they kind of "cone" rather than bend accross a clamp.
now the yz midvalve, there is a constant source of frustration!