i have a patio slab already done with 6 footers in place for 6 4 by 4 post.now i'm not connecting it to my house.i want to just use 6 2 by 6's,2 on each post.can i lag bolt them together?then should i use 4 by 8 sheets of ply wood or can i use 4 by 8 sheets of osb?the high point will be 92" the low point will be 84" that should be enough angle.am i correct?