Andy_K 

If by "slicks" you mean something like this:



and not like this:



or even this:



I'd say you're overthinking it. A minimal tread like this makes very little difference in performance.

Of course if you want slicks for purely aesthetic reasons, then by all means go for it. The Schwalbe Kojak is available in 700x35 at 330g with a folding bead. It could be just what you're looking for.