My end ileostomy was very comfortable and easy to use, but the loop was a nightmare. I had to remeasure the stoma at every change and had to cut the wafer at exactly the same shape of the stoma (not round, not oval, but the exact shape), which was not necessary with the end ileostomy. Mine was continually shrinking and sinking into my abdomen until the next surgery.
You may want to use the plastic that you remove to open the adhesive behind the wafer as a mold for next change, as it has the shape of the opening you had cut, so that it would not take forever to remeasure again at next change. You can cut a shape using that mold, and see if you need to make any modifications. You would need a small standing mirror to put on the bathroom vanity that you can see the stoma very clearly to make sure there is no gap around the stoma, else that gap may burn like hell. Your output will be very corrosive with the loop.