G'day Mowerfreak,
Just as a hypothetical, given the complexity of even a basic turbocharger/supercharger setup, why would you even think about using a G4? A small bore Keihin or Mikuni racing motorcycle carby is infinitely more tuneable...
And welcome to ODK, Ltdkc83. As far as the early plastic Victa wheels are concerned, have a little patience.
The prices that even the aftermarket repros are now fetching, will pretty much ensure that somebody in China will make and market copies, in time.