[Rainmaker]

The reinforcement depends on what you are using for poles. I ran with 12'-14' perko cheep riggers for a long time mounted on the Gunwale with little backplating with no issue. The riggers worked well but did break after a year or 2 in the bumpy seas. They were cheep enough that replacement cost was not an issue. I actually used to find them at garage sales and buy them when I saw them so I always had a couple extras. I think the last time I had through bolted the mounts and used a large washer behind the nuts relying on the wood in the gunwale for support... I would not recomend that but it did work. I would think a piece of angle or some other metal would work well for a back plate. It should not take much more than your rod holders.

If you go with longer and heavyier riggers you may need to use a thicker piece.

If you go on the arch you can still run the line from the rigger to a lower point, you do not need to get to the pole very often so you would not need your step as often as you think. I have my riggers mounted on my T-Top and have a fancy Top-Gun mount with a handle inside to turn them out. I attach the line down on the pole that holds up the top so I can reach it easily. This keeps the gunwales clear so that I can fight a fish past the rigger without having to go around the line. I fish a center console so getting to the bow is a feature I use.