I have been asked to build a slatted patio cover for a friend of a friend. He wants two 6X6 posts and a 2X6 header on the house. The support members from the header to a beam on top of the two posts will be five 4X6's and the "roof" will be 2X2's spaced about 3 or 4 inches. The total weight is relatively small, compared to a conventional roof. How can I determine the size of a beam (glue lam?) to span about 11 feet between the two posts. I'd like the beam to be either a 4X or a 6X. Thanks.