When we put the bracket, it's aluminum, on my brother's boat we mounted it 29" to the top engine mounting holes, the bracket was built at a 27" set back and it's a 25" shaft. Not the top of the bracket but 29" the mounting holes, if you want to simplify things I think the mounting holes are 2" below the top of the bracket, simple math and you are at 31" to the top of the bracket. I can't remember the formula for set back versus cav plate height, I think GFS knows it. If we had it to do over again we would have went 28 1/2", there is only one hole to lower the engine. Oh yeah we cheated, we had a forklift to help us position the bracket. You bought a fine bracket, good luck!!
Note how high Josh's bracket is compared to the bottom corner of the hull. Note post #18 should help you.
http://www.classicseacraft.com/commu...t=29289&page=2