He he, when I was 16 and taking my glider license back in 1986 we had to do a tow from a nearby field where we had been flying on a "camp" for a week even though it was a storm. Both my teacher and the tow pilot where 60+ and had thousands of hours and said it would be good practice for me as an apprentice
I have in my logbook with the entry:
1986-07-12, 50 min, Bergfalke 2/55 "Towed from boras in 90 km/h headwind at 700m, tow speed was 135 so it took ages! Landing circuit was performed by reducing speed to 70 km/h and reversing to end of field at 500m. Then fix the shadow at 90 km/h and descend until the ground effect caused a very unpleasant speed drop while still not moving relative to ground. Stick forward to get relative speed and landing with a roll out of maybe 20 meters..."
This was a school flight (my 14:th start) and my teacher who started flying in 1935 told me stories from the finnish winter war where they hovered the biplanes down on lakes in a similar manner. Reduce speed until the shadow does not move and be prepared to apply throttle when the ground effect kicks in...