Cool project! Looking up some ZX5 photos it doesn't seem too far off a "modern" 4wd buggy design despite its age.
I don't see front/rear shock position as a tuning option on the default setup sheet but that doesn't mean it can't be done?
I think some associated cars had front or rear of rear arm shock mounting as an option. Not sure of the exact effect of the change as i wouldn't think the leverage points would change. Either way, I'd just build it to the kit settings.
Kit setup:
https://site.petitrc.com/setup/kyosh...S_KitSetup.pdf