Dan,
I might suggest, for what it's worth, that a thermal isn't really quantifiable over time.
You might be able to take an instantaneous snapshot of a thermal in a two dimensional frame, measure each point and create an instrument to recognize that.
But the utility of that measurement will quickly decrease to the point of being lost as turbulence, temperature difference, wind and physical drift pass through changing atmospheric environments.
This is a challenge to a supercomputer and you, as engineer, are attempting to boil all this information into a few boops and beeps.
My point is, don't try to chase this too deeply.
Know when to stop.
The most important part of the Snooper is the pilot's brain.
We take that simple audio signal and apply some kind of fuzzy logic to it, creating three dimensional images of an atmosphere in motion.
You could probably present a slew of varying responses and our brains would learn, after a while, to successfully interpret each one.
If you have indeed emulated the original Snooper, you have completed the major part of the challenge.
It is now up to the pilot.
Future tweaks will be minor adjustments.
The burden of interpretation will always be left to the pilot.
The instrument demands a great deal of imagination to be used successfully in flight.
Some pilots have it. Some don't.
Don't let this confuse you.
You can be 100% successful in designing a "perfect" Snooper and some pilots will tell you it doesn't work.
Others will rave about it.
That has been my experience.