Raise both blades up so they are level with the skid and then adjust your top link so it sits level to slightly having the front higher than the rear (as you pull it will tend to pull the front down). I personally don't try to get material to spill over the top. Start off less aggressive to learn and then you can fine tune what works for you. My BEFCO would only allow the blades to go flush. I ended up drilling holes so I can now bring the blades about 1/2" above the skids. For my final passes I put them up that high so when the skids sink in to the gravel I've loosened it just skims the top and I get a real smooth finish. Otherwise the blades just dig up too much material. Personally I would rather have a small pile in front of the blades that will drop into the ruts you want to fill unless the road is in real bad shape and I'm doing major work. It might be slower but I'm looking to smooth out my drive, not move a bunch of material.