I too agree you're doing well, altho can't really tell balance from those pics. I also agree that you need to lower the heels a big more, level with or only a smidgen higher than the seat of the corns. I don't bother with bars generally, so long as they're passive to the outside wall. I do not generally remove any of that 'excess' sole unless it is flakey enough to come off with my hoofpick. I actually make do with a cheap knife, because I use it so infrequently.
I wonder about what appears to be very wide, red 'white lines'? Perhaps it's not as it seems, but has this horse suffered from laminitis a while ago? The pink rings around his white hooves is another sign. Is this the reason you're shortening the toe so much perhaps?
I would be doing a mustang roll, as you've done at the toes, right the way around the feet, especially at weak or faulty areas such as where Cat marked on that pic.