Need advice on hairball control

Hi - my cat Murphy (male and 14 years of age) is having some problems with coughing/vomiting. Maybe a month or so ago, he was vomiting on a regular basis, but I think I've got that problem taken care of as I believe he was doing so because he was eating a bit too much. For a little while, I wasn't portioning his dried food properly and he winded up eating too much and vomited on a regular basis. So the vomiting has stopped but now he's coughing and I believe it to be attributed to hairballs in his system (but maybe not). He hasn't actually coughed anything up, but when he does go into his little coughing sessions, it gets me quite worried that I can't do anything; I basically have to watch him cough until it's all gone. Also, I'm giving him the tuna-flavored hairball medicine (half-finger length every couple of days) that I got from the vet and his dried food is an indoor-formula w/hairball control. Murphy is long-haired and usually get's a lion cut every few months. After trimming him myself last time, I really do not want to go through that again (he's VERY non-tolerant and it took close to two hours) and it costs a bit much to get him groomed by someone who doesn't even trim him properly because he's that hard trim without sedation. So I guess I'm asking for suggestions other than getting him trimmed. When his hair is short, he doesn't have these coughing episodes so this leads me to believe it's a hairball problem. Should I give him a good shampooing/bath and brush his hair on a normal basis to get the loose hair off? Any suggestions would be greatly appreciated. Thanks!!!