Rotary delta is a new and very little used arm solution.
If you really want to use it, we do not have documentation at the moment, but the source code could be of help if you can read it, see here and rotarydeltacalibration.
[!NOTE] It probably does not fully work, and will need some coding work to fit your needs.
It is currently unsupported as no one has a rotary delta to test on.
Rotary deltas are also notoriously hard to calibrate, even homing is tough to do.