Thinking about adding a downrigger to my Gulfstream this year and I've been looking at the Penn Fathom Masters. I'd like to use the rod holder mounts as opposed to adding a fixed mount base to the gunnels. If I use the rod holder mounts, do I need to add a backer plate or anything else to reinforce the rod holder? Also, should I get a 2 or 4 foot boom? I'm thinking about the 4 foot boom in order to clear the outboard bracket. The majority of my trolling is offshore out of Ocean City. I appreciate any advice.