...especially if you confine the guestimate of the fraction of MD to 1/2, 1/3, 1/4.
As for working out actual drift I set track as heading & wait to see which way I start to drift. after a couple of deg. drift I re-intercept track & then use about 5 deg or 10 deg as a starting figure.
Wait & watch then readjust - bracketing any previously tried wind correction angles.
If you already suspect that there will be drift then don't use the initial TR=HDG: Make an educated guess & use 5 or 10 deg as the starting point.
With practice you soon become able to `guess' a suitable drift allowance based on rate of drift.