As others have advised, stick with convex wafers. Adding convex rings won't hurt. The goal is getting your stoma above skin level. It might be uncomfortable for a while... all that pushing down of peristomal skin.
You could add an ostomy support belt. Try the belt by itself over the convex wafer. See what happens. Still leaking? Add a convex barrier ring under the wafer. Put on the belt. The belt will maintain constant pressure. If still getting leaks, another idea: Using a 2-piece system with a snap-on bag... Place the convex ring under the wafer, install the wafer, then put a regular ring on top of the wafer around your stoma. Snap on the bag. So now you have a double seal. Put on the belt or try it without. See what happens. Remember to gently push and mold the ring around your stoma, both bottom ring and top. Note: Use gloves when handling rings, they are sticky. It takes a few times to get used to working the rings.
After recovering from surgery, the hardest task for an Ostomymate is finding a system and products that work for you.
You should consider consulting with a surgeon about revision surgery. A stoma flat to the skin will constantly cause you grief, especially an ileostomy. It's not too hard for a surgeon to pull your stoma out a bit.
After my surgery, I was pissed my colostomy stoma poked out so much. A little over a year later... I'm so happy my surgeon did this. Yeah, I gotta live with a big lump under my shirt. But I've suffered no leaks, and changing wafers/bags is easy.
Nu-Hope Corporation makes many styles of support belts. They are located in Pacoima, CA. They can be ordered from your ostomy product supplier. Amazon has a wide selection of belts. I've ordered quite a few to try out. They're not too expensive. If you're active, exercise a lot: Stealth Belts are good. Google "Stealth Belt" for their website. Wearing a support belt is advised when recovering from surgery, maybe 4 months or so. It's very easy to develop a peristomal hernia. It's not proven a belt will prevent it... but worth a try. And in your case, a belt might help prevent leaks.
"Charlie the stoma" love it.
Good luck