@Reto. Yes- thermalling can be aggressive tactics, but in my mind not necessarily risky.
It comes down to the way the thermal is drifting, the wind direction compared to course layout and your judgement of height gain compared to the position of other aircraft on the course.
It is nice to contact lift at an upwind distance outside the course that allows the full extent of working time to be used. During this circling period, the thermal drifts onto the course. You can then safely start with 4 minutes to go at high pace, with a substantial height advantage, and tactical advantage knowing that the thermal is in course, and extends below you and closer to base b at lower heights, so as you burn height chasing high pace, the lift remains with you. This is how to get 40 laps
Circling lift to follow it further away from the course is risky... This is how you get 20 laps when every one else gets 25-30
It's difficult for me to visualize Mikes 32 lap run. Was the course laid out in a downwinnd direction?
How many distance laps do you guys do in a 10 minute task?