the overall dimentions of the window is 51.5" wide 60" high the channel's only stamp is (28c) not sure on the weight load
Casey from SWISCO responded:
August 30, 2019
Thanks for posting!
It looks like you'll need the S380-29. Just be sure your balance measures 29" and the bottom shoe has a depth of 1". As long as everything checks out, go for the S380-29 with the 2830 option that corresponds with your 28C stamp.