Last night I patched thus:
Etherwave (pitch set so that it generates a tone even when not actively controling the vertical antennae).
into
MF101's audio in
(input will control range of influence - i found best results at 50-75%)
MF101-'s ENV OUT
into
any of the VGer's CV inputs
The MF's envelope follower tracks the etherwave amplitude (not the pitch). So with a setup like this you could patch the ENV OUT to the VGer's filter input and control the filter's cutoff freq with the hoop antennae.
OR
patch env out into the VGer's pitch input and control the VGer's oscillators like a regular theremin (but using the hoop antennae for pitch).
Another goodie is the patch the env out into the LFO rate in for a theremin controlled LFO!
It may be useful to process the CV coming out of the MF101 with the lag processor or invertor or both on the CP251 - I haven't tried this yet.