The only concern with using the onesize is possbily having it run on the incision. Just try not to make it to tight on her. If you see that she is tugging at the onesize, you may want to take it off for awhile so the area can get some air as well as calm down if it is irritated. You'll just really have to keep an eye on her and the onesize.
Good luck.
How is Daisy doing tonight?