I use pieces of 2x10 with the ends cut at 45 degrees. My longest one is about 6 feet and keep it in the truck bed for other uses too. I also have some shorter pieces that can sit on top of the long section. Knocking the ends down to 45 degrees helps keep them from moving. If I'm on the long board and need just a little more I then add one short piece for one of the wheels.
The more times you set up the more you will get a feel for what you need just by eyeballing the site.
I sold the plastic blocks in a garage sale.
