Op would you be able to try interactive feeding?
Have the dogs in separate ares of the house and put food around for the dog to find, soak food and stuff it in a Kong with something really tasty to encourage them to eat it obviously separation and making sure it has all gone before they are together are really important.
I would not leave food down as it may contribute to friction even if it does not appear to, it is also a missed opportunity to mentally stimulate the dogs.
What your feeding is a good food though.
I would teach the dogs to search and track especially if one is one lead all/ most of the time.
And hour and 20 mins per day is not much exercise if on lead, but I understand why on lead is needed. I would look for a few fenced fields I could use so the dog is off lead at least a few times per week, I would spread/throw food over the field for him to search and find/teach him to track/ search find and retrieve a toy.
Remember that you shouting at screaming at the time of an attack will increase stress/energy levels for all of you if it happens again do you think it would work if you were to walk through thwm and then remove the aggressor?
Three attacks in 2 years is a lot and I would separate the dogs when I am not there and have a short house line and muzzle on the one that attacks when I am- if you condition the muzzle correctly the dog will not be stressed by it.
The body language your dog is showing after are all indicators of stress which does not always equal needing reassurance often it is dealing with a physical stress and a surge of adrenalin can take a week or do to leave the dogs body so further incidents are more likely in this time and those signs often mean a dog needs space.
Often when dogs are close physicalyy signs are missed that one wants the closeness and the other is unable to avoid it fir various reasons- I hope a good trainer/ behaviourist can help.
