CRAN, you beat me to it: how on earth your throwaway line about R22/R44 has turned into a Robinson discussion just shows the narrow focus of some Rotorheads.
Without a doubt the concept of a 4 seater being only 30% more than a two seater would significantly influence a buyers decision, but your projected baggage limit is woefully small. 2.5kg per pax, without accounting for passengers weights?
Why would two seater weights be 95kg each, but 4 seater only allows average of 85kg each? I'd suggest a drastic rethink of the payload would be in order for this proposal to be attractive to the private market.