I am a fellow Missouri hunter, but I am way south in Marshfield. I am a die hard goose hunter! My suggestion is to dig your blinds into the ground if possible. The key to your success in an open field is concealment and a low profile! Try to face the wind at a 90 degree angle to where the birds are coming from and make sure to avoid the obvious of facing into the sun! High winds usually means the birds approach lower so a long thin spread is usually better. If there is little or no wind, open your spread wide and fat because the birds usually aproach more vertically and drop in. Under these conditions, I also place my decoys farther apart... Also, remeber that birds want out of the wind so look for depressions in the field that are lower than other areas. Also, most everyone thinks they have to hunt the middle of a field... I don't agree. Geese look for a spot that hasn't been eaten out, is out of the wind, and where they have good sight all around them... That doesn't always mean that the center is the best spot. Diagram your field and start x'ing out areas that are not a good place for geese versus what is a good spot for hunters and you will probally cut that 500 acres in half to help you decide where to hunt...
It sounds like you may have a great spot if you hunt it right! Good luck!!!