In the meantime...bought a used Tilton 3-plate set-up on ebay from a Nascar racer (with the wrong splines of course), just to see what the dimensions were and how much the parts weighed:
Kennedy 9" (228mm) dual plate:
Tilton 7,25" (184mm) triple plate:
:shock:
F*ck Kennedy, the Tilton set-up will be made to fit one way or the other! :twisted:
It will take time and probably too much money, but this seems really worth it imo.