I have now decided to have two teslas running side by side, one slightly higher that the other as I have 2 valves running anyway.
The higher coil will be for the treble clef and the lower the bass clef.
I have discovered on my music app that I can easily shift bass notes to the treble clef and treble to the bass clef. (still playing the same note of course)
This means that where single notes are sounded I could shift alternate notes to another clef and make the two tesla alternate between them for display purposes! Tremolos have never looked quite so good !!
I have found out how to put two independent tracks (bass and treble clefs) as a stereo pair so one step forward.
I don't think that there are any snags to my ideas but the proof will be in the
sparking pudding.