After my initial problems with PSK I have now got it all working 100% on the FT-757.
Hamscope won out as my software of choice and I am really enjoying the mode.
I have had more QSO (excluding contests) in the past 10 days than I have for quite a while.
I even made a small box to house the variable resistor for setting TX level and a switch for switching the audio and PTT out of circuit if required.
I also changed the PTT to work on pin 4 (DTR) of the 9 pin RS232 rather than pin 7 (RTS). The benefit of this was it stopped the transmit from firing up every time the software wasn’t telling it to not transmit.
This meant I no longer needed the PTT control switch but it is good to have – just in case.