In my rotary work, I did the opposite. Using a viable XY feedrate to determine an equivalent diameter based rotary feedrate.
Using the formula F{(115)*(XY feed)/(DIA)}A or {(360/pi) * (feed) / (DIA) returns a surface feed for the rotary. Note: My experience is based on using Vectric rotary wrapped machining, but the math is the same.
Here is an example showing how a diametrical feed increase would be devastating:
https://youtu.be/9bLnP9R7bE0During the flute cuts you can see that the feedrates are slowed by a slow (10ipm) Z feedrate during the sections that are closer to vertical