: I has heard somewhere poly could go over varnish but not the other way
: around. Anyone heard different?

It's the opposite and they were probably talking about one versus two component finishes. Traditional one-part varnishes can be used over the newer two-part urethanes (ie one-part varnish over two-part poly is OK). The two-part urethanes (usually poly-urethanes) are generally harder and more scratch resistant. They cure very quickly, are higher in gloss and are crystal clear and chemical resistant. Naturally they are more expensive but you need less coats.

Just don't try applying a two-part over a traditional varnish! The two-part urethanes contain some really strong solvents that generally dissolve the one-part finishes. You'd be applying nothing more than an expensive stripper.

Dan