Recommendation for a Kydex double-mag holder for 9mm S&W Shield PLUS 13-round magazine. Have a FOBUS Kydex for older Shield mags that doesn't fit the new wider "stack and a half" mags. Thanks.

Kytex Shooting Gear is my go-to for kydex mag pouches. Very high quality and reasonably priced. Here's their offerings for the Shield Plus:

https://kytexgear.com/product/...d-plus-mag-carriers/

Consider getting two single mag pouches instead of a double. Not only are 2x singles a few bucks cheaper, but it also gives you greater flexibility for placement on the belt line (like on either sides of a belt loop). And there may be times when you only want to carry one spare mag instead of two.