Have you used the hard plastic (UHMW or something like that alphabet letter soup) under your factory-installed shoes?  I have been replacing the shoes on my snowblowers at least once every 2 years.  I did find a place that will send you cut pieces to your specification at a reasonable price.  Just not sure if it is worth the effort and cost.  A 3" x 3" x 1/2" square is $6.50 and shipping in the continental US is $12.50 for 4 pieces.  New shoes are about $40 each plus shipping.