I'm assuming I missed the sarcasm sign on this one... If not, you're misguided here. The setup time will be awful. Just deciding on case and band options will take longer than it takes to activate an iPhone. Then, almost certainly most of the line will get a "how it works" tutorial from the sales team. It's going to be ugly.
No tutorial. Select watch and band, then pay and out the door. Apple stores don't handhold people -- if you need a tutorial, that's what one-on-one setup and workshops are for.
I agree picking a band and watch type/size could take time, but no more than activating an iPhone.