The tamiya one you show seems light... you could sand it carefully on 1000 sand paper to remove the extra thickness.
I bought a RW spacer a few years ago, but it was maybe 3mm thick which seems to much for you. A bit on the heavy side, too, which is a bit annoying when you are trying to remove weight from that very location of the car by moving the motor away.
I love wedge bodies. I love dish wheels.