The matting at the base of her tail and along her back, is because she can't reach it to keep it clean. I have had long hairs in the past, and one at the present time. I prefer a comb. The comb tends to go closer to the skin, whereas a brush, only does the top hair. How about trying something like Science Diet hairball remedy....light. Also when switching foods, do so gradually. 1 part new, to 3 parts old brand. Then half and half, gradually switching to all Hairball Light. Good Luck!