Ok , Ok I get it , sorry for misunderstanding you. The reality is like most things in life its only scary the first few minutes. After the first hole drilled today , it was easy peasy. I cored out holes that where 1/8 bigger than holders, sealed inner edges etc. I also stopped at my local machine shop and had 8"x8" 1/4" alluminum plates made. I figured they would distribute some of the pressure of my imaginary 1000 lb tuna. The reality is after the first holder I installed A quickly relized that the backing plates that came with the holdrs had a bit of flex in them, Although very stiff. The fact that i could crank the back plates tight and have them semi mold to under rail, seemed much stronger than having a huge plate floating.
I mean you can make the surounding area as strong as you would like but the reality is , the holder is only as strong as the rail. needless to say I installed them all today , And im very confident that my holders will stand up to my imaginary tuna. A may or may not in the future ,reinforce botom of transom holders. Thanks yal!