Programming DTS Deltas on Hog 500 without fixture library

[Lightup]

I've struck a problem with a rig I've programmed which includes two DTS Deltas. I don't have the software for them so have patched them in using two desk channels and one CMY each.
I want to use one fader to be a colour stack so in house audio ops can just press play to change the colour. So i've selected the desk channels and the CMY's and recorded them as a group. From there I've recorded colour palettes with the intensity at full.

So, the problem is that when I record to a fader I need to be able to control intensity by moving the fader up/down but there seems to be some sort of weird control issue. When the fader is anywhere between about 5-95% the fixtures go through all kinds of strobing and colour step modes.
I've tried using 'crossfade IFCB' in the options for the fader and that doesn't seem to do the trick, which it has done for other LED fixtures I've worked with in the past.

Any suggestions please?