I've had cats all my life and right now have a long haired, 14 yr old, ragdoll cat and hairballs are a big problem for her in the spring and summer especially. She doesn't like petromalt much and is allergic to something in lots of foods so I have to be careful. Once I find one she can tolerate I tend to stick to it. Right now she's eating Purina Indoor Cat and seems okay with it. But...that's not your question. :rollseyes:
I found that brushing daily works better than anything else I've tried. In fact I keep her brush next to where I usually sit on the couch and when she comes for a cuddle I brush her. Sometimes it's several times a day and I cannot believe how much hair comes off that cat during hairball season! No wonder the poor things ingest so much and have to cough it up! Anyway, try brushing her a lot and be consistent about it and I think the problems will lessen a lot.