RE: Futaba-JR compatibility
The majority of JR Rx's are a single conversion type therefore a single conversion crystal is mandatory, a dual conversion Futaba crystal cannot work.
Another factor which I do not beleve applys here is Futaba Tx's sold in the North American market are negative modulation shift and JR uses positive modulation shift therefore there can be no compatiablilty.
Agine check locally I understand that Futaba in other parts of the world default with Positive modulaton shift as does JR.
Your Servo plugs should be electrically the same for either RX and the Futaba plug need only have the flange cut of with a hobby blade and otherwise no problem.
John