The stoma size will change. I can't remember the timeline exactly but maybe 6 weeks to 3 months before it settles down on a size. Is the ostomy nurse having you use an Eakin seal or something similar to compensate for the size change. That 1/4 difference may cause some issues. Also, maybe trying a moldable will help as it molds around the stoma creating a turtleneck effect. I know ConvaTec and Hollister make them. It maybe worth trying. I had a hard time with the one piece as I couldn't see through the bag well enough to put it on due to the flush stoma. I ended up using a 2 piece system and it was so much easier and less room for error.

Again, it takes some time before you find something that will work. And, what works now may not work in a month. Check out the different companies websites and if there is a system you think might work, request samples. I went through a lot of different samples to find things that would work for me. Hang in there! I'm rooting for you!