if you have a series loop, you would only need 3 sensors to do all those various virtual sensors.
all rads in series, going to sensor - GPU - sensor - CPU - sensor and back to rads. If the pump is in one of those positions, then that's two sensors only that you need
If you loop rads between blocks, that will require more sensors for intermediate readings
One for air would be very useful too to get the water to ambient temperature difference, commonly used for fan speed control, auto adjusting all year long if your room has no AC (since radiator efficiency is directly related to that value)
you can use any combination if inputs to make virtual sensors, or reuse the same physical sensors several times of course. Any sensor reported to Aquasuite can be used, from hardware ones in the Next pump, temperature sensors, flow sensors, but also the ones from hardware monitoring, HWinfo etc...