I you ever need a rod holder with increased height you can check out the RAM. My glass DB doesn't have a gunnel and I do want my rod to be almost parallel to the water so increased height anchored from the front seat is a positive. This is good for those on the sticks on a glass boat.
This company also makes mounts for GPS and just about everthing. It may not be the best solution for many applications but it was for mine. Bob from picatorialpursuits had recommended this one. Just a thought!
So what do others use in this situation? I have fish-ons in the front.
ram-mount