may sound uncat like but ..I put mine in the basement tub every other week and water them down..they get used to it..im very gentle..that helps wash the dander off of them..also instead of vacuuming furniture I bought a big sticky roller that way the hair and flakes are picked up and not put back into the air..I also found the longer I had the cats I became more tolerant of them.
I also heard a little vegatable oil on the food helps keep skin moist..hope it works out for you