fix bracket on 23 cc?

[carpapia]

I AM IN THE PROCESS OF PLACING A FIXED BRACKET ON MY 23 CC. I PURCHASED IT AT THE DIANA FLEA MKT,IT IS A DOUBLE WITH THE DIVE PLATFROM. IAM PUTTING TWIN 200 OPTI MY QUESTION IS AT WHAT HEIGH FROM THE BOTTOM DO I PLACE IT? THANKS FOR THE HELP FELLOW SEACRAFT OWNERS.