Try the new associated team / factory B4 standard setup with step pins, you shouldn't have any traction problems. I race on a very similar track, ruts and all. You just pick the best line you can and go for it...
You might have better luck using silver or green rear springs, black is really soft.
From kdubs post on rc10b4.com:
New Kit setup (for team and FT kits):
Front: #1, 30 wt, no limiter, Brown spring, 25 block, axles down, 2 bumpsteer, shocks 2-Out, link 1-A, 1 washer, -1 camber
Rear: #1, 30 wt, 2 limiter, black spring, hubs middle, 2 antisquat, link 1-C, 2 washers, shocks 1-In, -1 camber, battery back
This was developed over months of testing to make the car easy to drive. It works best on low to medium grip tracks, indoors and outdoors. It has good rear traction and jumps flat to nose-up.
Typically when I run this, I run either 32.5 wt mix oil or 35 wt all around. I also like a bit more down-travel all the way around. For higher grip tracks, try shortening the rear link to 'B' in the hub or going up to Green rear springs.