The RTz mount is for the long-nose. Great design, works really well. But it's too far forward for the short nose.
There are/were several short nose mount designs out there but none are really striking as far as functionality. The front of the short nose is just in a bad spot. Empty space up to the thin sheet metal above it.
An example, looks like what ArizonaZcar used to offer. Maybe they still do. Uses the control arm tubes as mounting points -
https://technotoytuning.com/nissan/240z/z-power-cradle-short-nose-r200r230-and-ford-88
Many of the short nose options have been discontinued. Many of the early designs had problems. Too much leverage.
p.s. I'm on CZCC too. Zed Head.