The wheel weight making a huge difference is, at least in my experience, a bit of a myth. Years ago I had a cyclocross bike that came with what were best described as boat anchors, some 2500g a pair, and since I had ~1900g MTB wheels on my then current daily driver I tried them on the cross bike. The same tyres as before, the same cassette, only the wheels themselves were changed.
Expected all kinds of great things for such a weight loss, got... very nearly nothing. It may have felt slightly more responsive, or then it was all in my head, but what is absolutely certain is that it didn't become any quicker by any measurable criteria.