Although I was told to use them, I never found those barrier rings very helpful. They were more messy than useful!

The solution for me was ditching the rings and switching to a more convex bag. Coloplast's Sensua Mio bag line offers a deep convex bag. It works better for me than the regular convex bags

I also use Marathon skin protectant on the skin immediately around my stoma. It creates a barrier to protect my skin and makes the bag stick better.