strut spring spacers??? Miata specific

Looking for a GRM way to increase the ride height of my miata. I am currently running a set of racing beat race springs for the 1.6L, fatcat 99' upper mounts and fatcat bumpstops. My arse end is running a bit to low and still running out of travel. I know fatcat sells the 1/2" spacers but I want some way to test if raising the car just a bit will make it handle the way I want. I don't want to spend a bunch of cash now, because next year I am going with the full monte fatcat custom coil overs. Anyway I was thinking of using some nylon(actually a kitchen cutting board) and cutting out spacers for the lower perch then using some pvc pipe around the shock shaft to keep the spring centered. Does this sound reasonable? Anyone else have something even better? I am very open to suggestions!
Thanks Paul

You will love (no, LOVE.) the FCM coilovers.

I've never used the Racing Beat springs you have, but the '99 mounts are supposed to provide an extra half-inch of travel. Something sounds fishy about your setup if the rear is lower than the front. Got any pictures?

RB springs do have a tendency to run a little low with age, and those NB mounts only make the car lower. The biggest problem is just not enough travel for your spring rate.

A hacked up cutting board sounds like a good plan. Just watch out you don't put the suspension into coil bind by putting a spacer under the spring - if you think it rides badly now, you should feel what it's like when your spring transforms into a solid tube!