I reload quad strong-hand, out of AP Customs (much preferred) or Taccom holders. IMO, but the deuce and quad shotshell holders work better mounted on a vest than on a belt.
For outlaw 3-gun (by the way, why is it still called 'outlaw?') you're going to want at least 12-16 shells on your person, at a minimum. I'd also cast a critical eye at the sidesaddle. If it works for you, great, but I've seen shotgun sidesaddles get in the way of other, faster loading techniques.
Josh is right about the Swarovski Z6i, it's the best 3-gun rifle optic you can buy. The Vortex is nice too, but heavy, and doesn't have the bright center dot of the Z6i. If I had to replace my Z6i, I'd get a
Leupold VX-6 Multigun.