either or would be grand. I like packers also. I like the combination of chopped meat with slices. a lot more fat in the point though but thats alright.
7 lbs. is nice. I like to get the packers from walmart too, they are big and not enhanced here in Indy. However, at Sam's Club they only sell flats, but they are very big flats - sometimes up to 10 or 11 lbs.
7lb. flat is a good size. I do way more flats than packers, but been on a packer roll here of late. As Craig said your yield will be about 4-5lbs. I would suggest cooking the flat "high heat". Good luck with your cook.