Max drift
Surely to avoid a circular arguement we need to agree the purpose of 'max drift'.
Based on W/V forcasts we calculate the heading to steer and groundspeed (time). We therefore minimise off track error. A major concern is that we do not infringe Controlled airspace, Danger/prohibited areas and other places nor unwittingly hit anything. We therefore consider an assumed off track worst case scenario in deciding on our intended track.
Radians devised by the ancient Babylonians (the marsh people of Iraq) worked this out for us thousands of years ago. In aviation we call it the 1:60 rule. BEagles 'clock code' as he saids is simply that, Wv v TAS, The change in heading by the pilot that then changes ground speed and will prevent drift has nothing to do with worse case scenario calculations.
You must decide the worst case scenario to use, be it; 15 degrees (1/4), 30 degrees (1/2), 45 degrees (3/4) and 60 degrees (the lot) but applied simply. Max drift needs to be no more complicated than that.