If you have the space I personally wouldn't prune, the only time I prune is to constrain the vines to a certain area. The vine will stop producing fruit once it has all it can handle by very small fruit either rotting away or female flowers shriveling and never opening. If you limit the number of fruit on a plant you will get bigger fruit, which to me is undesirable. I would much rather have a ton of smaller fruit than few beautiful large fruit. This is because winter squash easily store over 6 months if stored properly, but once you cut into one it is a race against the clock to use it all. And I suspect the average family doesn't doesn't go through 20 pounds of squash in a few days unless you really like it!