I didn't have too much trouble with them at the Death Valley 100 that the
Bumgardners ran a couple of years ago, but there is no sand, soft going,
mud, water crossings on the ride. It was almost entirely road and track.
I understand that putting Easy Foam in the boot so that it has a snug fit
works pretty well but I haven't tried it so I can't say. I gave up on
Easy Boots for anything other than emergency use long ago.
Additionally, I found that if I put them on so that they didn't come off
every 100 feet (exaggeration), then I would need a pry bar to get them
off (not an exaggeration). If your friend has a horse that doesn't stand
still for having shoes nailed on, he sure ain't gonna stand still for
putting Easy Boots on and off. However, if he puts them on fairly
loosely, and has to reset them all the time, maybe his horse will get
used to having his back feet messed around with and pretty soon will
stand for the shoeing.
kat