Ok, I misordered some almond/bone colored filament as 3mm, and the 1.75 is no longer available. It's PET+, but the color is perfect for my project. PLA is not an option due to low temps. Anyway, I see in the R1 forum that a new hotend might be required, but the R1 is a different design. Anyone use 3mm in the R2? Is it even possible? I don't care about the filament runout detector (I can stuff it with some 1.75 to fool it). If it fits (a big if), it seems like just dropping the feed rate a bit might make it work.