Vettec Superfast and wall repair...can I do this myself?

I pulled horse’s hind shoes a couple weeks ago for the winter. He’d been shod behind about a year, being barefoot prior to that. We had put shoes on because he was getting too much wear, and the vets wanted more support on RH. The vets were ok with me pulling the shoes, and he’s been sound and moving fine since then. I pulled the shoes when the ground was nice and wet and soft. But we have had some high winds the past few days, which have turned the mud clods to rocks, and that plus really fresh horse this morning (high winds and cold), and my horse has really torn up the hoof walls at the heel quarters and over the nail holes. I went out and put more clothes on him, which quieted him right down, but the damage was done. The nail holes were a bit higher up on the RH foot on the outer wall, and the breakage there is the worst with some exposed white line. There are a couple other chunks taken off in front of the heels, but most of the other problems are just a little bit of shelly wall right at the bottom of the foot. The weight bearing structures are in good shape…heels, frogs, toes…as well as the soles. I’d been painting the feet with iodine/pine tar. Maybe we should have done a stronger quarter bevel during the trim, but the farrier tends to leave a little more wall when first pulling shoes, and unfortunately that wall was just too weak from the nails. I rasped off any sharp bits and rounded edges of the chipped parts so the cracks don’t grow.

I’m a little bit concerned about how much has broken off of RH, although he doesn’t appear to be tender. I knew there’d be some breakage, but there’s a bit too much exposed for my comfort especially on lateral RH. We’ve got a month to go till the next trim, and my farrier isn’t the easiest to get out in the middle of the cycle.

I’ve watched some videos on doing wall repair with Vettec Superfast and think I could figure it out well enough to cover any exposed white line at least. He behaves better for me rasping the hind feet than the fronts (fronts are still shod and fine), but he still doesn’t stand with the best manners. The instructions say to have the horse stand on their plastic wrap stuff or cardboard while you fill the crack. Anyone know if I could use one of their adhesive foam boards instead in case he moves around?

I don’t think I need to balance out the sole side of things, since the damaged parts are not the weight bearing areas and more of the outer wall broke off than we have full width chips, so I don’t think I could do any damage screwing up the balance, but am I being delusional in thinking I could do this? One concern is that it maybe won’t all be grown out in a couple spots by the next trim, so my farrier would have to contend with my work and not just cut it all off.