On a Gamma 5800 it takes me about 45 minutes watching tv from start to finish for a 2 piece gut/poly job. This includes cutting out the old strings, cutting open 2 new string packs and cutting the bundles in half, putting the remainders in ziploc baggies and labeling them. Mounting, stringing, and re-gripping. This is on slow pull, doubling the crosses with a pedal.
If it was a 1 piece, limp syngut off a reel, not watching tv, with the racquet already prepped and mounted I'm sure I could do it in 20 minutes. But that would be me going full out and doesn't sound like much fun
I guess the point is all the other "stuff" that goes with it usually takes as much or more time.