draining mash and sparge

Hey Folks: When draining the mash how fast do you allow it the go? Let it rip with the valve wide open or let it out slowly? I don't really know my efficiency but it is decent 70-80%. I am usually around the correct OG when I plug the numbers into Tastybrew. Close enough for now. I have been letting it run out fast. Yesterday I decided to slow things down and let it run out much slower. Thoughts anyone? Thanks Charlie

Well, what kind of sparge are you doing? Fly sparging, you want it to take a good hour or so. Batch sparging, you're just draining the wort, not rinsing it, so no reason not to just let 'er rip.

I sparge. I'll let 'er rip. Thanks
took 14 minutes for answer!! This always impresses me. Charlie