RE: What shot size?
4, 5, and 6s. 6's for a lot of shot---but not quite as much down range knock down power. I shoot high velocity 4's in my 835 using a .685 Hastings choke. Patterns well with lots of knock down power at the longer end of the "envelope." 6's would be great 30 yards and under---but as was mentioned you need to pattern a couple of size shot.