My Kossel Mini Delta is up and running (my second printer, first one is running like a well oiled clock - Prusa i3) very well with Rich's FW and auto level did a very good job as I do not seem to have any issues with first layer sticking or head running into bed etc....I am currently printing at 240C (chinese E3D is approx. 10C off, so that would translate to 230C on my original E3Dv6 with same material), 70mm/s and Owl looks quite nice, but the top is somehow "open" (look at the picture). I minimised tiny blobs with retraction of only 1mm at end of loop and extra retract distance -0.9mm before continuing. Coasting is set to 2mm. Otherwise I had tiny blobs at end of loop. I use 3mm filament in bowden, head is 0.4mm.
I do not think under extrusion is the issue as top/bottom look very nice when I print 20mm box (3 top/bottom layers filled). Might it do something with retraction?