Though my delta has two hotends, I've never tried dual extrusion with it. I just finished the traffic cone on my Big Box dual, using the experimental S3D profile created by Greg Holloway. I'm pretty happy with how close I got on the nozzle offset for a first go, but I noticed a lot of heaping of filament when the first nozzle was laying down infill on the first couple of layers. This had the second nozzle hitting little nubs of plastic and getting bumped around in a worrying way. I calibrated e-steps/mm for the T0 (I know there is a script to change e-steps with tool changes in the profile, but I left that commented out for now), and lowered the feed rate to 85%, but I wonder if there's something else I should be doing to minimize this problem. Is it just overextrusion? Also, I'd welcome any other feedback. Looking at this photo, it almost seems as though I have some Z-banding, but it's not as evident to the naked eye.