I'm very impressed by your work here!
I'm wondering if any of these tuners support IQ data streaming and tuning; browsing around I saw some mention of IQ data only working if a valid DVB stream was tuned at least with some tuners?
My interest as you might have guessed is if these devices can be used as general purpose SDR receivers, and it looks like this project might be pretty close to having the required access to the hardware.
Alternately, I'm also curious if there is any major difference between the tuners wrt. FFT spectrum capture performance?
Even if IQ data is limited (at least for the time being) it might be interesting to use these as VHF/UHF spectrum monitors (with an appropriate front end mixer).
Best regards,
Robin