Didn't you say you took a bucket of gravel and spread 2 inches? That it lasted for a period of time. I was trying to suggest spreading 4 inches of gravel 6 or more inches may even be better.
this bolt idea has me interested. ive worn down 2 sets of steel teeth on an 805 preseeder and am looking at putting on carbides this time around at a cost of 1300 just for the teeth plus my time and weld rod to put them on. I'd be curious to know how long bolts would last.