Here is an example of a rig I built for myself. Consists of an RRV, Padded MOLLE Belt, and a Hydration BackPack.
I am using 3 Double NMAG’s (1 Left, 1 Center, 1 Right), 1 Single NMAG, and a FireStrike holster on the Chest Rig. Mounted with Large BARS. Medium BARS could also be used which would allow the NMAG’s to be mounted 1 row lower.
The Battle Belt uses the ButterFly style Single NMAG’s (1 Left and 1 Right). Any of the offsets or center style will work here. I liked the symmetry of this set up because it makes the edge of the furthest magazine line up with the edge of my HammerShot Holster on the other side. I am using the Small BARS on the belt.
The BackPack can hold a ton of extra magazines, spare batteries, another blaster, lunch, etc.
This rig has changed many times over the course of development, but it has managed to stay this way for a while now. It works well for both 12’s and 18’s allowing me to carry 9 magazines plus one in the blaster for a total of 10. So between 120 and 180 rounds.