Hi, I agree with Penguins, try a convex flange, and also try using stoma adhesive powder, then paste around the opening of the wafer.
It's also important as to how you clean your skin. I never use soap....ever. I gave it up 50 years ago (under the wafer that is). I don't take off the wafer in the shower because even shampoo can leave a residue.
I use hot water to clean the skin around the stoma, and then cold water (to close the pores). I then use a prep wipe....(which really prepares the skin) and removes any lingering body oil/moisture.
I put the powder around the stoma and before I switched to the moldable flange, I used to put a ring of stoma adhesive paste around the opening of the flange.
I have been using the Convatec 2-piece system for many years, but about 2 years ago, I switched to the moldable flange.
The opening isn't "cut to size". Instead, you stretch it with your fingers, to widen the opening, fit it around the stoma, and then the extra wafer forms a collar around the stoma. It's been great....and I rarely have a leak. And if I do...it's minimal at best...giving me enough warning that I need to change. I hope this helps.
Marsha