Hello,
I use a 2-piece Hollister too. I have a colostomy, 16 months post-op.
I used to use just a wafer. I had to cut the wafer hole to precisely fit my oblong stoma. Too much hassle and time wasted. Plus, the wafer by itself was uncomfortable.
Then I learned about moldable barrier rings. Game changer for me. Now I cut the wafer hole with a lot of clearance all around my stoma. Takes 2 minutes. After test fitting the wafer over my stoma, I set the wafer aside. I grab a barrier ring, put on gloves, cut through one side of the ring, then gently squeeze and pull the ring until it is long enough to fit completely around my stoma.
Standing in front of a full-length mirror, I gently attach the ring. Starting at the middle of the ring, at the bottom center of my stoma, I lightly press the ring onto my skin. The inner edge of the ring is right against the base of the stoma where it exits the skin. I work the ring up both sides of the stoma. At the top of the stoma, both ring ends come together. It does not matter if they overlap or there's a small gap.
Then I install the wafer over the ring. The ring seals to the stoma and skin, and the wafer seals to the ring and skin. I've never had a leak. And I've had some very full bags. It used to take me an hour to remove a wafer, clean around my stoma, and remove residual adhesive. Then cut a new wafer to precisely fit my oblong stoma, then slap it on. Now I get it all done in 15 minutes.
I change the ring/wafer every 7 days. My peristomal skin remains perfect.
I use 2-inch diameter rings, 1/16 thick. I prefer Coloplast Brava rings.