i would go for a 10 inch cement anchor, as the size of the concrete determins the strength of the posts. fpr the metal bracket, i would use the one that sits on top of the cement and is bolted on. u just have to place a 1/2 x 10 inch carrage bolt with a washer at the head in the concrete, leave 3/4 inch above the cement to fasten the bracket with a washer and nut. put a wrap of masking tape on the threads of the bolts to keep cement off and the nut is then easier to install