The variable that challenges the whole process in the flight levels when doing science is the changing groundspeed during the turn.
I don't think that this has anything at all to do with mental arithmetic in flight; this thread is more to do with aircraft & procedure design, by engineers. However...
Accounting for wind is most easily done, not by changing groundspeed, but by simple calculations of constant TAS in a turn, and (separately) the time that the aircraft is affected by a constant wind.
So, if an aircraft does a 180° turn in a 60kt wind at rate 1, forget changing groundspeed. Instead, calculate radius in nil wind, then move the aircraft 1nm downwind at the end of the turn.
PANS-Ops Doc 8168 (instrument procedure design) has many beautiful diagrams illustrating this principle.