The best advice has been given, I will re-say it, the best way to figure out what works for you gear wise, is go play!
I went from running just a couple of small pouches on a BDU pants belt, to a full battle belt, chest rig combo.
I am slowly graduating more onto my belt, so that for longer games, I can take off the chest rig and be battle-ready with just the belt.
My advice is, keep it simple, keep it light, but keep it to what you actually use, not what you think you will use.
Mine now consists of 2 M4 Mag Taco pouches, 2 double pistol mag pouches (4 1911 mags) dump pouch, canteen, small utility pouch, kill rag pouch, and a holster for my sidearm. Even with just this, I find it gets a bit heavy, need to keep it tight, and use suspenders with it for long term wear.
This allows me to be ready to respond if needed, but I can easily just toss my chest rig on for a battle.
For a skirmish or indoor game, I dont even bother with the chestrig, I add a couple more mag pouches for M4 mags, even just run a bandoleer or carry some in your pockets.
Running just a belt is feasible for the right situation.
But again, go out and play, that is the best and really only feasible way to find out what works for you
4 years since I got all of this loadout, and I am still always changing things around or adding/subtracting.