HEAVY sled pulling

[b fold the truth]

Was wondering if anyone on here ever did much heavy sled pulling. Later this Fall I will be in another contest and will be pulling a fire truck for 100feet and am currently training with my sled and with pulling my truck.

I've been doing some sets on my sled with between 4-500lbs (sled is much much heavier and harder than most sleds because of high friction...not smooth) and pulling my truck after doing legs and atleast once on another day. I'll pull my sled for 3-4 sets of 75-125 feet for time, like doing sprints. I'll also pull my truck for 2 sets of 125 feet (5k+lbs).

Anyone else have any other suggestions.....

Thanks

B True