Depends, I guess. Are you using only the belt, or combined with a PC or chest rig? You using a basic 1-3/4” inner/outer setup, or something more substantial?
I usually have a flapped double rifle mag pouch on my belt since they ride lower, more comfortable than the passive retention ones like kywis that sit higher. It’s no more bulky than a holster, so it’s not too hateful to wear. Double pistol kywi behind an esstac flapped double rifle, TQ in front of the holster on my other side, med mag in a horizontal pouch on the rear. This is on a Trex speed belt.
Not much reason to carry more than one or two sidearm mags, unless your pistol is your primary weapon for some reason.
Thinking about ordering a JSTA pouch and lunar concepts rifle/pistol insert and replacing the double pistol kywi with that, since that bit of extra storage would line up nicely with the width of the double rifle pouch, makes for a decent loadout of 3 rifle/1pistol without getting too crazy.
Depending on what you’re carrying, it might be worth looking into suspenders of some sort. I can get by without, but they definitely keep everything much more stable when doing dumb shit.