Hi Patty, Not sure if you're new here or just been lurking. Good to hear another professional voice here! I usually explain that I appreciate we've got but a few pics & a little info, so what we suggest is always to be taken as 'food for thought' & possibly not accurate if we had the hoof in front of us. I also tend to speak in generalisations, as IMO there are precious few hard & fast rules.
horses are NOT mustangs with mustang feet and will not comfortably tolerate having all the wall removed from weight bearing. They NEED the inner layer (the un-pigmented) of the wall to share the load with the edge of the sole.
I agree that domestic horses AND mustang's(I'm presuming we're talking the arid rough environ mustangs) load should be shared between wall & sole. I think different people interpret a 'mustang roll' differently & to me it doesn't at all mean removing the entire wall from weightbearing. The inner wall should absolutely be there for support.
BUT ASSUMING it's healthy & well attached. When the hoof wall is already compromised, such as lamellar wedge & stretched toes, then IME it may not be in a position to take a support role & may need to be relieved in order for well attached material to grow down. Leaving unhealthy/flared wall can cause soreness too. *When walls are compromised, the soles are usually too thin too & they may well need padding while they are bearing the load while healthy wall grows down.
Even Gene Ovnicek, the ORIGINAL researcher of the feral foot does not do a "mustang roll" on non mustang feet.
I would say whether to do(or how much to do) a mustang roll comes down more to the environment the horse lives/works on.
And maybe use some sole hardener such as Rickens sole freeze or Durasole on them to harden and dry them. Everyone wants to panic about little stuff.
No panic here, but I think a lot of people think this suddenly means the horse is capable of rough ground without protection. If the soles are thin, they may be marginally better with hardener, but still thin & at risk of bruising & such, so I think it's best to protect/support them where needed.