I hope it's all right to post this question here, I'm hoping to get advice from all you construction experts on this. I'm a mom who wants to build a good, large, sturdy, basic A-frame to hang 3 swings for my boys. My oldest, at 14, is already 6 feet tall, so I'd like it to be big enough to allow him to enjoy swinging along with his brothers. I bought 4 10' 4X4 posts for the legs, will those be long enough? Should I exchange them for 12'? I know I'll also need some 2X4 pieces to make the cross-piece of the A. I bought another 10' 4X4 post for the top. Will that be long enough to hang 3 swings from? Should I get a 12' one instead? Will it warp or sag some day? Should I use a different cut of wood instead? My biggest question is how do I attatch the top to the legs? Should I attatch the end of the top piece to the legs or leave a foot or two hanging over? I know there are several different methods I could use, metal brackets, wood braces, sturdy bolts, & others. I want to make it strong & secure, and very safe for lots of use. If you could post close-up pix of your set, I'd appreciate it. Thank you!