Hi Rikki
From what I can gather, Receptor is like my Wersi Abacus in that if the sounds/Styles etc, are assigned to a button or preset, they are loaded into Ram at start up, (The Wersi OAS instruments have no Rom Banks) obviously the more instruments you want direct access too, the more Ram you need.
Also on my Abacus, all Buttons and controls output Midi codes, so that I can just use the learn function of the VST (Which with Wersi OAS is loaded direct into the Abacus) to assign what buttons I need, so I would check to see if your Ketron will do the same, rather then having to use a separate keypad.
With most manufactures now combining computers and hardware controllers together it should be interesting to see what’s new at Frankfurt this year.
Enjoy.

Bill