I have three 4'x7' (approx) thermopane patio doors which I wish to turn sidewise and use for windows in an enclosed porch. I plan to fabricate side jambs and frame tops from 5/4sx6 and sills from 2x8 green treated stock. I plan to incorporate integral external stops (such as used in door frames) in the jambs and frame tops, but I have been unable to locate jamb stock crossections to determine typical stop projection dimensions. I would appreciate access to sources for this information.