Hello Alfred,
thanks for the tips. I remember doing some rough and ready test in 2015 when I started using AD, to see if data entry & internal precision for the Rotate amount was any better than its display precision. Well somehow, I can't remember how, I convinced myself that high-precision data entry for Rotate wasn't the thing to do, and went cursing and muttering back to Inkscape as need arose. I've just run a couple of simple tests and proved that AD's Rotate transforms can indeed resolve much better than 0.1º. I'll eventually satisfy myself with more elaborate tests addressing precision limits, but I'm happy for now. And I certainly didn't know about the facility to enter integer fractions in Rotate, so yes it helps - I'm sure I'll occasionally find use for that.
Cheers,
Marcus