I was deployed when the battle belt rage first happened and after sleepless nights thinking about the modularity and all the shit I could put around my waist, I ended up having one sent over to me.
Initially, I was like Fuck Yeah! I can move some of the shit from my carrier; or even add more shit as I need it!
Then I sat in a vehicle and basically sat on half the shit. Getting to the sidearm was a disaster. The damn thing started to rotate on my hips both in the vehicle and when dismounted. It had a weird matrix of, it fits and then now there's a 4 inch gap in it because I'm crouching. It got worse when laying in weird positions against terrain or in just weird positions behind cover where it was a grab bag of fun choices like, why is my pistol infront of my dick, or, why does my fucking hip bone hurt so badly being dug into this magazine pouch with a full 30 round mag in it, or my favorite, why is this dump pouch trying to sling itself up between my legs and constantly attempt to hit me in the balls.
Then there's what happens while you have to run and move. There was a lot of that. The people who usually chime in with 'my belt stays where it is all the time!1!111' generally only use it looking tacticool at the range and/or don't ever fucking do F/M bounding. Here's a test for your battle belt; put all the shit you need on it. Now go sprint 30 yards, stop, sprint 30 yards, stop, sprint 30 more yards. Now try and do flip onto your couch. If you're fat, your belt is now around your chest. If you're not, the belt is at some weird angle and rotation trying to make itself some kind of weird hip thong. The battle belts strength is its weakeness; you can put a good amount of shit on it. The weight for all of that is what makes it bounce around and move, regardless of how well it fits when you're standing there staring at yourself in the mirror.
The only real way around this is an inner velcro belt that's on your pants that anchors the modular belt, but in that case be smarter and get a inner velcro belt with an exterior gun belt that you can add molle onto like the AWS system, or already has molle on it like some of the Volund or Ronin. Why? Because you can scale it instead of having the entire modular belt there the entire time. I also wouldn't hook on to anything via the D ring on a cordura battle belt. personally I use the AWS outer belt with the molle panels as needed and have a Snake Eater inner belt.
I know someone is going to link a picture of some SOC guys or mean looking contractors with a battle belt on to prove their point. Two things; thats probably from around 2006, and if you see the one with some SOC and DoD guys, I'm the one with the miltech MVM marked combat shirt and the pink colored ballistic glasses (which I still have!) in the picture where you see the emblem mural on the wall behind us from when 2/2 moved into Kandahar.
Scale your gear. You sort of have the right idea with the belt but I would honestly go with a carrier (chest rig for practice) as your 'base' and scale from there. Chances are you won't move much around on a carrier (chest rig) because that's your fighting setup. You can bring just that and leave anything else behind, or scale and bring it. You'll have your armor, hydro, primary mags, IFAK, comms gear (wheres comms gear go on a battle belt?) and any misc shit you need. Need a pistol because you'll be mounted? Get a CRYE MBITR suite pouch that you can put a smoke, frag or 2 mags in and instead secure your pistol in it; mine is on my carrier at 2/230 so its either supplementary magazines, smoke or I put the sidearm in it which is easily accessible while seated.
Then scale it with the belt. You have a secondary mission specific weapon you made me tote around all day; well the mags for it are now on my belt at 8 o clock. Move your sidearm off your rig and into the holster on your belt. Need more primary mags to get to without rummaging through the truck or your ruck, they're on the belt. Need a GP pouch for specific mission items for just today? Belt. Yet if your belt were to disappear down a river, or fall off a cliff, outside of your mission specific shit being lost (shame on you!) you still have your primary ammo, comms, hydro and armor.
I know this is for a class. But you're going to that class to learn how to shoot better and ultimately should it come to that, shoot at people. Would you only take a battle belt to that? If not, why train with one as your primarily piece of gear?
ETA - Best holster setup on the planet is a Safariland holster with the GCode adapter and GCode duty mount. The only problem I've ever had was when drawing the pistol, sometimes the bottom of the holster would want to tip outwards because its attachment point on your belt is much higher. You can fix this by buying a single Sarfariland leg strap, unscrewing the GCode RTI wheel and running the strap through it. Then you have a simple leg strap that holds the holster down and it won't try and flip outwards when you draw.