My wife's 88 Paramount came with six speed Dura Ace 7400. The wheels are MA40 with freewheel type dura-ace hubs.

The six speed does not really work for my wife. So I have been SLOWLY collecting parts to make this bike a nine speed.

But I am unsure what to do with the wheelset.

I have been considering trying to find a 36h dura-ace 8/9/10 speed hub (probably 7700) and having the rear wheel taken apart and built up with the new hub. I am guessing this would cost me at least 50 bucks for a used hub, 36 bucks for new spokes, and 30 bucks in labor (don't know how to do this myself)

Would that be a good idea? Is it really cost effective? Or should I just sell the wheels and buy comparable 8/9/10 speed wheels?

Pictures of bike/wheels at issue: