Side saddle for more ammo, buttstock ammo carrier (W/cheekpad is nice!), and an extended Mag tube. I also have the enlarged safety button which allows me to snip the safety off with the side of my trigger finger without changing my firing grip on the gun. That's all you need for a CSG.
The slings which carry ammo are no good. They're heavy with ammo on them and swing all over the place, no good.
And of course, the admonition of Dave McC...BA-UU-R.
"Always place your clothes and weapons where you can find them in the dark"
"Understand that the enemy is not the enemy in his own eyes ;this may offer you an opportunity to make him your friend. If not, you can kill him without hate, and quickly."