Since reviewing the JM Customs AIWB kydex holster I have added a neoprene wedge which JM Customs sent me. I have also been carrying with the CCC AIWB Gestalt kydex holster and will continue to until I have enough experience with it to do a full review.
Gestalt on left, JM customs AIWB on right, neoprene wedge.
It is recommended to use standard 3M hook/loop
to attach the neoprene wedge to the holster and figure out what the right setup is for you.
to attach the neoprene wedge to the holster and figure out what the right setup is for you. 
Neoprene wedge on the Gestalt.
Neoprene wedge on the JM Customs AIWB holster.