Clough42 - I also have interest in 1.75 mainly for availability issues rather than function. However I have an inventory of 3mm and would like to cover both. Any chance of getting an STL of an extruder block with 3mm on the right and 1.75 on the left? Or is there a liner tube out there that goes from 3mm to 1.75? if not, there should be.

/quick search shows 2mm ID 3mm OD pfte is available. Maybe a good way to go, possibly even reversable once installed.

I am a Happy IBD user although I'm kind of over dual material printing since the self support in Simplify 3d is so dang good - Thanks again.