PA Tuning Tools Fails on E1, E2, etc

[retsamedoc]

When attempting to use an extruder other than the primary one (E0), Klipper had the following error:

Unable to infer active extruder stepper

Turns out that we need to add an EXTRUDER= to the SET_PRESSURE_ADVANCE command. Perhaps the Klipper Pressure Advance tool should include an option to specify which extruder is being targeted?

[AndrewEllis93]

Hi @retsamedoc
I am testing support for this on my variant of the PA site. Looking for feedback.
I also put ACTIVATE_EXTRUDER EXTRUDER=<name> before the start g-code, but I'm not too familiar with multiple extruder printers. Is that correct? Are there any other gcodes that need to be added?
Site: https://andrewellis93.github.io/pressure_advance/pressure_advance.html