I built the interface and Peter's pulse generator onto one board
as you can see the fixed resistors in Jeroni Paul's interface have been replaced with pots, giving me total control of the R, G, B, and mixed syncs components.
I don't think I ever sketched out a schematic! I'll try to resolve that for you later today, although I think it was literally swapping fixed with variable resistors. The sync coupler remained 10uF
Here are the odd & even field waveforms from the board. (only showing the last 1 or 2 lines of peak white video before the v sync train)
