cc1, welcome to the forum. I hope you enjoy your visits here.
I purchased the magazine holder from Mr. Hedley when my holster was ordered for the R9S.
I'm still undecided about where to keep it, while carrying in the right front pocket. There has been a temptation to put it under the holster bottom, but that doesn't sound very smart, for some reason. Perhaps it could go in an unused rear pocket?
Away from the body, one good choice might be to put it in the glove box or unused ash tray.
Could someone tell about their solution for having extra ammo on the body?
Bill