i never cook the sheets of lasagne, just lay them on top of the meat sauce and white sauce sprinkle of cheese ,then repeat the layers with the top layer just white sauce sprinkle of cheese and brown in the oven for 45 mins . it is easier when you use the dried pasta ,as you can just snap it off to get a perfect layer in your lasagne dish ,and you only need to use sheets in a single layer if you use double sheets of pasta that might make it chewy and uncooked ,or perhaps your meat sauce is too dry ,it should be slighty on the sloppy side ,i don't think the brand matters ,i use asdas own cheapo brand and it cooks perfect every time -hope this helps