HI,
in shortage of OS9 RTAS synths Iīd consider some Hardware as Access Virus A or Clavia Nordlead 1 or Waldorf microQ lite or a Clavia Micro Modular.
they go pretty cheap on ebay are great synths and good to dich out some serious punches on the dance floor, plus they donīt steal the power from your dated G3 and will have less latency and can be controlled via MIDI CC, too
have you check
http://www.refx.net already?
regs