Cheers. I'm guessing then if the logic for the drive hold etc. is actually fully self contained within the respective "FT feature sound slot", then an alternative method would be to keep the 201 (etc.) file as is, then just add the FT sound slots, drive hold, run8, brake, coast? I assumed (obviously incorrectly) that the actual drive sound needs to be "FT compatible" but if the logic for drive hold isn't in the drive sound, then virtually any diesel loco can be given the FT features I guess?
I must say I have been wondering why several ESU files are not marked FT and are missing the drive hold slot, but DO have the other FT features. In the description it always says for these files "this is a normal idle project". I assumed because of this that the drive hold feature was not simply an additional sound slot, but required modification to the actual drive sound, hence the lack of "FT" in these files descriptors.