A 300 bushel pit is better than no pit but if you're going to put a pit in, it needs to be bigger than 300 bushels to really get the benefits of a pit/leg combo.    It really needs to be at least 500-600 bushels of usable pit space to allow a semi to pull in, crank the door wide open, pull ahead and start dumping the back of the trailer while the driver checks on other things, takes a leak, grabs a pop/sandwich, etc

A 5700 bph leg with a properly sized pit should really speed up dumping grain.    With a 500+ bushel pit you should be able to have a 1000 bushel semi in and out of the driveway in under 10 minutes very easily.       That's the kind of setup that I dream about having someday.   

The value of that setup would be huge if you ever find yourself really short on help.  Like what will likely happen as your current help gets older and unable to help.  


I'd even go as far as trying to design it so that someday in the future you could add another 500 bushel pit and dump a truck without moving it.  That could get you in/out in ~ 5 minutes/load.