Here's my setup from UK National at Kidderminster 17-04-2016. Medium to high grip short pile Astro Turf.

I had an issue with my front diff caused by me building them with an extra seal internally which broke up and partially seized the one outdrive in the front diff making the car very difficult to drive. I took the diffs out before the final and found the fault and as you can see from the video from the final the car was massively improved.