Maybe I was not clear in my explanation - I agree FC temperature is roughly predictable, what I was looking for is something like an ETA based on the current RoR etc. So if I am five minutes into the roast, the ETA for FC temperature might be 7 minutes and I’m aiming for 9 so I lower the power a little and watch the ETA change (much like a GPS navigation which would change your ETA to destination based on your speed). If I lower it too much say by six minutes I see my ETA has gone out to 10, I can increase a little to try and get back to the target.
At the moment I go by the readout on the R1, so say at 5 minutes in, my RoR is 15 and my current temp is 160. If my target is 9 minutes, then I’m estimating/predicting 4x15+160 = 220 which is too high, so I lower power and/or increase fan and then I recalculate in my head. It would be nice if the software on the laptop could keep doing that boring calculation at interval (15s?) and display it. I used the analogy of a pilot on an instrument glidepath coming in to land knowing he’s not too high nor too low for the runway based on his rate of descent. Something like that for arriving at FC temperature at a given time.
A display would be fine if amending the graph to project forward is too complex, but both would be nice