This is one of the few areas I believe I can offer some very solid advice, as one of my best players is/was a special teams gunner.
http://goallineblitz.com/game/player.pl?player_id=2301535Started playing gunner full time in season 28. Seasons 30-34 he played with Asau in World League and had some very good success, even in season 34 when he was declining.
When I hit plateau I had strength at 92.1 and tackling at 94.1. In retrospect I wish I had neglected agility a bit to push tackling and/or strength a bit higher.
I understand your point about the higher weight but I have a feeling tackling may play a larger role then we think for FF's. That, and the fact that I couldn't pass up Speed/Strength/Agility/Tackling as majors from the combo SS position.
I'm sure that if I were to build him again I would be more efficient across the board.