Well I am late but just found this!!
Tell who ever told you this to stick his info were the sun doesn't shine!!
I have a 1975 V20 Cuddy, full transome with Stainless marine bracket with full swim platform, and 25" shaft 175 hp Evinrude.
Here is my boat at reat in the water
as you can see I am out of the water more then most transom mounted motors, and that is a 30" set back.
I have never 2nd guessed myself after I was done!! The boat performs, better now then it ever did!!
She gets on plan fast, more adjustment with the trim, and handles great!!
I guess the only draw back it that its slow turning takes a little getting use to cause it is now a 23 footer then a 20 footer.
I have never taken a wave over the motor except once, and that was when a ten footer hit me!, But the top of the motor never went under even when boat was full of water and listing to one side!!
As a matter a fact I say the Bracket saved what could have made a bad situation worse!
When the boat filled with water from the wave its the floatation that kept the motor up and its the bracket that got hit from under with a wave and saved the day!
go bracket and you never regreat it!! Just do it right!!
what else do you want to know?