[rfuerst911sc]

I have a early 70's Boston Whaler that I purchased as a fixer upper. At some point in the past someone had done a partial transom replacement it looks like the top half was replaced. The nearest I can tell it was done well and is solid and dry. I am at a point where I'm ready to hang the outboard motor but just to be extra safe I'd like to install some aluminum on both sides of the transom so the motor is clamping to the aluminum rather than the fiberglass. Boat will be trailered and only used in fresh water. In this scenario does it matter what alloy I use ? Should I use a 5000 or 6000 series ? I'm thinking of using .100 thick and it will have adhesive caulk and some screws drilled through the transom to hold it in place, plus the motor clamps and thru bolts. I'm probably over thinking this but I have a lot of time in this hull and want to be extra careful with the motor install.