Your stoma will shrink some after surgery. You might want to have it checked out. I know that a retracting stoma can be a sign of disease returning to the intestine. Don't get alarmed though. I'm no doctor and I'm only speaking from my own experience and by talking to my doctor. Have it checked out. It's probably nothing.
As for the leakage. I know many people who like Eakin Seals. I've tried them but I prefer the paste. I think it's just a matter of preferance and whichever one makes you feel more secure. you might want to try a convex wafer or insert. It makes the stoma stick out a little and helps reduce the chances for a leak.Also, I always "picture frame" my appliance with hytape. It works the best for me. Unfortunatly trial and error is the only way to find out which works best for you. My first year with an ostomy was very frustrating for me. Although, I only leaked a few times, it was always at the most inopportune time and made me feel very insecure about leakage. Now I never even think about it. I haven't had a leak that wasn't my falt(trying to stretch out another day with the same appliance)in about 16 years.