Tested this setup yesterday.
Using a 2mm gap 3" insulated tube cell
Pulsed the primary with a 50%dutycycle squarewave from about 200hz to 20khz.
found 2 sweet spots were the VIC resonated that were @ about 4.5khz and 14khz.
However unfortunately there were no phase shift as I was especting

i.e. voltage sinewaves were same in amplitude and in phase at the +ve and -ve terminals, and therefore no substential potential difference across the cell.
What I`v learn from these 3 experemnts is that
1/ water in between the electrodes should be totaly isolated from ground.
2/ earth ground connected to SM isolated ground seem to help in achieving VIC resonance better.
Still disappointed with the results so far

HM