Day late on the updating here. :)
Elvis is doing well. The continues presence of paint in the air doesn't seem to be bothering him since a) it's mainly latex right now and b) I'm remembering to turn fans on after I'm done. It really does seem to be the oil-based paint/primer that works on him...which I totally understand, so I'll be more vigilant in turning fans on.
Nothing else is really going on with him. The increased Pred has handled that horrible cough, though I won't know if it's really gone until he goes back to his regular daily dosage next week, but so far so good.
I'll probably post another update early next week unless things change.