There are bits to be salvaged from Ruhl (1989), perhaps, but it might be easier to start elsewhere entirely.
I fully acknowledge there is certainly an appeal for monosemy as a theoretical construct. The ability to schematize all usages or senses within a single abstract sense does indeed simplified and elegant semantic theory. Such a theory is an attractive prospect for all linguists.
Generative grammar has moved on from its old theories about syntax. Can we please do the same with their semantic theories, too?