Whew! Learnt the academic 1 in 60 rule which was used for basic flying training - worked like a charm!
When arriving at a checkpoint selected at distance gone that divided into 60 reasonably easily - 15 20 30 - mapread to see the distance off track left or right. So 1Nm off to the right at 30Nm tracking 2deg right. 1 Nm right at 15Nm tracking 4deg right.
Then a corrective turn (double drift) to regain track in the same amount of time to the checkpoint from your set heading point, followed by a turn back onto track with a heading adjusted for the drift experienced to the first checkpoint.
Went something like this (20 Nm Point with 10 min elapsed). " I pinpoint myself on the river between Newcastle and the railway bridge, I should have been 3 miles left of the bridge, I am 5 miles left of the bridge, therefore i am 2 miles left of track which means I have drifted 6 deg left. My heading was 070 deg therefore I will steer 082 deg for 10min and then 076 deg.
Its independant of groundspeed and works
For Nav test purposes this had to be achieved before halfway on every leg.
In the real world - turn onto heading - pick a point on the horizon and fly to it.