They are both low temp covering and both fuel proof. Try using Windex or a home brew of just water and ammonia to put your trim on then after it has set you can just go over about 1/4 inch of the outside seam to make sure it stays down. I haven't tried the ammonia on TC or EC but it works great on Mono, doesn't work at all for Ultra.
Like Les I use one covering only these days, Ultra, but I still like Mono for trim work.
Other then electrics I have had very bad luck with the EC and TC coverings. I have had EC shrink so much in the hot sun the covering split, looked like someone took a razor blade to it.