I've spent the past 2 days setting up Marlin and TouchScreenFirmware. I decided to try and set it up for the dual heater zone strategy just to see if it could even be done before I bothered to actually go down that path.

Here are the shownotes of things I learned:

• There has been an alternative heating method to PID in Marlin for a while that I've only now found out, called MPC. This reddit post shows the difference and it looks like the superior method.
• Marlin considers a mixing extruder as 1 hotend, even if 2 thermistors are specified. This causes a tad of an issue with MPC and I needed to add and modify some things to get around it.

• To use Marlin Mode on the TFT, the EXP cables are still needed. This means that, had I actually tried using an 8-in-1-out, I wouldn't be able to use the Octopus Pro v1.0 I already have and instead would have to get something like a BTT GTR (I don't think anything else other than a Duet would support >=11 axis)
• Additionally, it seems that Marlin only supports 6 mixing extruders at the moment.
  • Thus it really sounds like the strat would've been a Manta M8P V2.0 + CB1 + Fysetc AIO and Klipper, or something to that effect.
• C5, 523 Hz, sounds ok on the buzzer
• The Octopus Pro doesn't need the SD card after flashing, meaning I don't have to sacrifice a £3-from-AliExpress, 32GB microSD.