I built a steel arch building 10-12 years ago, 51 wide I think. I just lined up a row of the "Texas blocks" on each side and, had steel U-channels bent up and anchored down to them, set the edges of the building in them and bolted together. So far, the blocks haven't moved, and the building has withstood some heavy snows.

My goal was to have a truly temporary building. When I decide to hang 'er up, someone can unbolt the building, pick up the blocks and move(and re-use) the whole works. Should be nothing left behind but some gravel.

Ours is American Steel Span brand, if memory serves. I think all the Quonset style buildings are about the same, but there are real differences in gauge of steel used and the coating. We have 2, the other is a Miracle Span, the Miracle is regular galvanized which has dulled and the American has remained brighter. I have seen them listed on Ebay, best deal I found when I was shopping was pricing at the farm shows. You have to be hard-nosed with them, it's about like buying a used car. Offer them 30% less than they are asking, chances are they'll come down more than you have to go up.

I can try to get pix for you, if you are interested.