Sorry, I don't have a recipe handy but just a hint or two.
I have stuffed the shells UNCOOKED and poured the sauce on then refrigerated the dish overnight before baking. This makes it easier to prepare and seems to work fine. Also, my husband doesn't like that "metal taste" that tomato sauce sometimes has when it comes from a can so I find that adding a little bit of sugar takes the edge off of the aftertaste it can sometimes have.

Go to Search TKL and type in manicotti and I'm sure you'll find several good recipes. Personally, I like the ones that have spinach and cheese filling.

Good luck!