Someone please give me a clue!
Ahem! Let’s put a few things straight again.
Your radio is FM, end of story. PPM and PCM have nothing to do with the FM radio. PPM and PCM are ways of encoding the data, PPM is analogue and PCM is digital. PCM is slightly better at dealing with interference. You will need a matching PCM receiver from the same brand as the Tx, PCM Rx are more expensive. PCM allows failsafe programming. For most people, PPM is fine.
Dual conversion has nothing to do with selecting the frequency shift, and servos do not recognise any difference in shift. Dual conversion is purely a receiver process that blocks image frequencies from Tx that are 2*IF away from your frequency from causing problems, and it also blocks similar problems from frequencies that are multiples of yours. DC receivers are more expensive than single conversion and needs the DC crystal, your sc crystal won't work in it. Most people find that single works fine but DC might be preferable in the radio environment where you operate. The Tx most definitely does not need a DC crystal because it has no idea whether the Rx is SC or DC.
Frequency shift is a problem made by Futaba purely for the North American market, so that other receivers will not be compatible with Futaba Tx, and other Tx not compatible with Futaba Rx. It is a marketing con to lock you into Futaba products. The data coming out of the Rx is always the same though, so any brand servo can be used with Futaba and likewise Futaba servos can be used with any brand Tx and Rx.
Harry