I have a somewhat different opinion, or perhaps 'perspective' is a better word, since I'm closer in handicap to moonducks and have been struggling with taming a slice. I think that if you are having issues with slicing and are willing to go out to the range and work it out, sticking to a single club isn't a bad idea. Switching out different clubs isn't going to really help sort out a fundamental swing issue, and I think it can really complicate things because of the subtle differences in how you swing longer and shorter clubs. (For me anyhow.) If the 8 iron is slicing, the 7 will probably slice worse. And once you figure out how to tame the 8 iron slice, you're on the road to fixing the 7, etc.
Have you talked to your local pro? Sometimes the price of a lesson(s) is lower than the time and frustration (and range fee many places) required to work it out yourself. Beyond that, think about your swing plane, that's where my slice lurks waiting to rear it's ugly head when I get sloppy and start coming over the top. Videoing yourself can really help too.