A On-road engine might be the ticket. I run mostly on a similar track and use a fully modded Picco P9-R with one tooth extra on the bell. It suffers slightly from soft bottom punch (compared to a P7-R), but sub0.4mm squish and 34% fuel (by weight) makes it quite good. If it grips when the engine starts to pull some wheelies will occur with the buggy. Runt time is around 9-9,5min.
It sure looks like you know how to have fun over there! Nice tracks and the best beer... Would you welcome a fugitive from you´re friendly neighbors in the east??