bear with the explanation please.

I picked up a 29er beach cruiser as a current project. I'm changing it from a single speed to a multi. and found a rear wheel that uses a cassette. I really don't know much of anything about them as all my other bikes are old things that use a spin on cluster.

the seller stated that the hub was for a 8-9 speed cassette, but I really just want 5 gears. just hunting around on ebay all I see is one that's kinda costly, plus I'm not even sure if it'll work (5 speed uni-glide?).

the reason I just want five is I want to use an old muscle bike shifter that is a click shift. someone at the co-op said I could just use the 8-9 speed cassette, and just set the derailleur stops to just use a range of 5 gears (grouped together on the cluster i mean), but I'm thinking the gears would be spaced to close together and not match the shifter throws. I'm also thinking maybe I could take the shifter apart and see if I can make it work like a friction shifter with the 8-9 speed cassette if I have to. I have a 5 speed friction shifter on a 7 speed with shifter throw to spare (another reason i'n thinking the extra gears are closer together).

I guess if all else fails i'll just look for another shifter to work the 8-9 speed cassette, but I'm hoping there are options I don't know about (truthfully, I'm wishing I had stayed old school and used a spin on). thanks.