I have never used any patterns for hunting in the fields. Normally I'll place a look out goose about 40 yard in front so I would know my distance when they would come in. I'll place the feeders in front of me in no particular pattern with a couple of look outs on the outskirts. You should get good distance with the 3" shells , about 40 to 50 yards.
As to breast the birds out , if that means cleaning them, just peal the skin and fillet the meat out same as deboning a chicken breast. Practice make perfect. Good luck in your hunt.