FWIW Sparks double IWB mag pouches, for my single stack 3913 mags, carry nicely between my Wranglers and my Wilderness Tactical Frequent Flyer belt.
Secure and a bit more comfortable than when carried IWB of the Wranglers, combined with a IWB Summer Special or Executive Companion holster.

Stills conceals well under a cover garment.... like a vest or "fishing style" shirt which are my normal casual spring summer fall casual wear. "I need the pockets" Phone, reading glassed, keys etc..

The Wilderness Tactical belts are infinitely adjustable for fit, so works well for with either IWB or OWB carry.