I use two seperate pieces on my alto. I use a Lakey 5*3 and a Selmer C* Short Scroll Shank. It's normally not a problem to switch between pieces, but it mostly depends on the diameter of the shanks. Thankfully, the two I use are close to the same size shank. My friend, however, used two pieces on his tenor and they were different enough that the wider diameter mouthpiece always seemed to fall off. He got the cork expanded and hasn't had any problems. If the cork on your tenor neck is already compressed because of your current piece, I'd get it expanded. Find another mouthpiece you like and, as long as you don't really use one more than the other, you should be fine. You might have to get the cork expanded every once in a while, but it's not a big deal.