I don't really understand these holsters with a mag pouch sewn on them. If you carry strong-side, how do you reach your spare? Maybe you have really long arms and a small belly? Do you change hands with your pistol and swap mags with your strong hand?
For me, the quickest reload is to carry on my weak side, and use my off hand. Maybe I've been dong it wrong all these years?
Anyway, when not wearing a covering garment, I use an old nylon wallet with the mag and a small light carried in my left rear pocket. The wallet helps protect the mag from lint somewhat and keeps it from shifting position.
With a cover garment, In a Wilson combo that carries one mag and my Surefire 6P.
Always carry a spare, even with hi-caps. Some malf's are best cleared by dropping the mag in the gun and reloading with the spare.