I found this in a magazine and decided to try it. So glad I did! I made it for the first time last night and it is really great. I used 9 oz. fresh spinach instead of the frozen spinach, and it worked great. My husband even liked it, and he is not normally a spinach person. I used most of a 26 oz jar for 1/2 a recipe, so you may need more sauce than called for. I'm sure you could use homemade, too. Be flexible!
Also, this recipe makes quite a bit. I am cooking for two people, and I froze half the stuffed shells for another time, and there were still plenty of leftovers. Freezing them works great! I flash froze the stuffed shells on a cookie sheet, then dumped them in a ziploc and stashed them in the deep freeze. I let them defrost for a day. Then you just have to add sauce, and cook! Perfect weeknight meal, but good enough to serve to company.