I think when you get to Grants Pass and see the terrain you'll see why they use the concrete blocks. The provide the necessary height and stability they need on that loamy forest floor.
At my home course, I prefer the 8" wide pavers. They are just heavy enough to hold the targets and light enough to carry easily.
You're lucky you can get away with the wood bases.
Associate Match Director DFTC
"It doesn't get done til someone does it"