8 isn't a big spread, but if you are in the right location you should be ok..
Try adding some movement, flagging really can make the difference sometimes..
I made my own fags, just stapled some black material on a 1x2 piece of wood. The material is about 2ft sq - when the geese are at a distance, try slowly waving the flag while calling. I really believe adding the motion makes a BIG difference..
Main thing, keep scouting, make sure you are where they want to be,