1988 Deore 6-speed cluster

[bodrobert]

Try to take a spacer from the left side of the wheel to the right side. It is possible that after that you have to pull the rim to center, it is easy to do with loosing the spokes on the left side and tighten the right side spokes by the same amount.

 

[velomaniac]

Surely you could custum build a new cassette by taking apart an old hyper glide cassette and rebuilding as you desire. Dremmel down the internal sprocket flange that is specific to the hyperglide freehub so it fits the uniglide and then all you'd need was a uniglide outer lockring sprocket. might be easier to find just the lockring sprocket than the entire cassette.