I tried a Scotty 429 gear head mount extender rod holder on the side rails of my PA and it had too much leverage on the side rails, it was actually moving the side rails.
Nice looking Hobies you have!
After putting some slight pressure on the Scotty setup attached to the hand rail, I can definately see what your saying about too much stress on the rail. I may go ahead and just mount it to the left side mounting board. Yesterday, I did order a ram 1-1/4" ubolt mount to attach my fish finder to the right side grab handle. I want that as close to me as possible!