Hello, I am in the design, materials-gathering, stage for my hen house. I'm planning a 12x12, 8' wall, shed-type roof for my house. I found a great price on some used Big, slider windows, but am scratching my head on the best way to frame around them. The longest one is 68 5/8" long x 35" tall, two are 52 5/8" long by 35" Tall, one is 52 5/8" long by 43" tall. (So the longest one would span 1/2 of my wall) Should I use 4x4s since they are so long (hard to find ones untreated) or can I double-up on 2x4s? Would 2x4s provide enough strength on top and bottom for that length of span? How would You Frame Them? Thanks in advance for any help!