Ended up with 0.6 Pressure Advance, the settings above, print speed 60mm/s with outlines and perimeters set to 60% and 70% of that. Retraction had 0.05mm of Extra Restart Distance in Simplify3D and with those settings, everything looked pretty good.
I was inspired by d42 to get into building a large delta. … I used smoothieware as at the time duet was in transition from 0.8 to ethernet/wifi (over a year ago). If I had to do it again, I'd go with duet -- I had a lot of trouble with the Azteeg board, eventually switched to authentic smoothieboard.
[Admin note: I'm very sorry, I accidentally edited your post instead of replying to it. Feel free to re-post it - dc42.]
The calibration algorithm assumes that the bed is flat and the geometry is accurate except for those things that auto calibration adjusts. If your build has other types of geometric error or a non-flat bed, it will give incorrect results.
Calibrating diagonal rod length automatically is not advised unless you are able to probe points a long way outside the triangle formed by the towers.
Don't worry about the delta radius being not quite what you expect, unless you have distorted prints. Print a noughts-and-crosses/tic-tac-toe pattern that goes right up to the edges of the printable area, and check that the lines are straight.
Thanks. I'm on a 0.1mm height calibration object right now around 130mm radius and it's looking pretty good.