I don't have a lot of dual extruder experience at this point, but it seems apparent that ooze from the idle nozzle is going to be a constant battle, especially with PETG and other oozy materials.
I'm wondering if it's possible to create a tool change script that will move the print head off-part, toggle temperatures on nozzles, and then wait for them to stabilize before continuing to print. Thinking that a temperature drop of 40C, for example, should keep the idle nozzle from drooling. I understand the time implications of this practice, but I've been working with one part where the secondary nozzle only prints on the first layer. A 5-10 minute delay to print the first layer would be no big deal on that part.
My first thought is that I'd need to have two tool change scripts to accomplish this, and S3D only has room for one, unless there are ways to use conditional statements in the script.
Thoughts from the GCODE masters out there? FWIW, printer is a Makergear M2.