How to Design a Good F/V System for the Volume Oscillator?

Hello everyone! Brand new to theremins, and I mostly got the hang of the pitch part, but the volume is being a pain. I have the following volume oscillator setup:

Followed by an LC tank to boost the far-hand frequency and a peak detector

And finally a long-tail VCA

With this setup, I can get a pretty okay signal out of the Env node:

However, I don't know what to do to change these levels, and the red signal (which represents the hand being closest to the antenna) is not high enough to saturate my NPN at the VCA. My setup is mostly cobbled together from tutorials and schematics online, so I had a few questions:

1. What is the best approach to designing an F/V system for the VCA? Is there a known best topology, or a known simplest topology, or is it kind of a try-it-and-see-what-works deal?
2. Is my VCA good enough, or are there any immediate issues with the rest of my setup? It seems like most setups I find online use an integrator, but I could not get that to work.
3. Are there any resources where I can read on the volume oscillator and the concepts that go into building one?

Thank you all for your help and patience

Not entirely sure what I did but after messing with a lot of values I got a good signal out.

Hi scrapwitz, welcome to our community. I don’t see any major flaws in your approach (there’s no ground connection for V6 in the circuit). This long-trail VCA should be able to cover a range of about 40 to 50 dB. This dynamic range is roughly equivalent to that of a cello or a violin; these instruments can be played quite loudly, but not extremly softly as needed for the theremin volume control. With the theremin, on the other hand, you need a range from extremely quiet to very loud. This means the dynamic range must be larger. I would therefore start with the VCA and improve it. Also the R25 can be adjusted to better match the env signal. 

What successeful value changes you have made?