With fft_bin_bits = 14 can be connected 8 independent users with CPU of RPi3 lower than 80% (72-79%), stream is smooth and waterfall is usable. I'm tried also 10 connection, but this is with small drop-out, when someone is tuning (CPU around 90%). For now is set "maximum_clients = 8".

Thanks for support and hard work also for "non company" devices. Can you add my server to the public list?

I'm waiting for availability of HF+, then im exchange rtl-sdr dongle with my home Airspy Mini dongle.