Right, I've now installed RideRunner, Carwings and RRFusion for v6 brains onto a second system alongside FuseGL with the same test setup; one v6 brain, two temp sensors.
Again, I'm able to toggle digital outputs immediately; no setup required. But the reading of the analogue inputs is pretty much unusable. I have one port set as a thermosensor, the other as raw voltage, and 99% of the time I get a reading of 0V or -4 degrees on both ports (and I've tested all the ports). The other 1% of the time the data will swing all over the place; 59 degrees, 63 degrees, 198 degrees, then back to -4 for another period of time.
Considering I only plan to use my brain for input readings (no output control required), it seems I'll have to embed FuseGL into RideRunner until this issue is addressed.