summerstorm! I think you got that reversed!!! The plastic cover side has the 'sticky' part...
A sure seal basically protects the wafer tape from water...it's breathable and waterproof...kinda like Gore-Tex for ostomies!!!
Here's what I do...I trim my wafer so it is smaller than the sure seal (I use Convatec now and the paper part of the wafer is TOO BIG), that way I can leave the sure seal in a ring. I have an uneven stomach so I have to pull areas level to get a good seal (NASCARon I think it is similar to your issue). Before I put on my pouch, I take the plastic cover off the sure seal (try not to touch the sticky part...especially the edges) and center it on my wafer (I pull my stomach to make it flat) and when I am sure I have it in contact I pull off the the paper part (which doesn't have any sticky to it)...any 'bubbles' I may have I pull my skin flat and push down on the 'bubble' with my other hand and I can usually get a good seal...they are stretchy so they will 'adjust' to any application errors.
I find my wafer tape will last at least two days longer since it doesn't get wet...they aren't the easiest to get the hang of and it's taken me many modifications but I finally have it where it does work well