Lightweight warbelt / 1st line gear set-up

Basically, I just want something that is low profile, lightweight, but padded for comfort as well and supportive. I want to carry my G19 and 3-4 spare mags, perhaps some 33-rounders as well. I’m starting from scratch, so I’d like to get it right the first time. The basic idea would be that this is a grab-n-go SHTF type setup that I can slap on in a hurry.

The other issue I’m wrestling with is a suitable holster for my Glock 19 with this type of setup. Right now, the only holster I only is a Serpa which I’m presuming can be attached if I bend the STRIKE platform I already have to fit. I don’t want any drop-leg style holster, as I want to conceal this whole thing, if possible under a baggy shirt or jacket. Trying to keep it as low-key as possible.

Thoughts?