Take a look at Drift Master Rod holder's, have many options for installing, and all type of degree's. I use 1/2" S. Steel Pro Duo Rod Holders, they are a 2 position Rod Holder, 1 is a 30 degree, great for eeling.And the other is 0 degree, great for pulling Rigs from the side of your Boat. I have 10 on board. With 6 types of base's for mounting, you can position them anywere on your boat. All my Rod Holders are mounted on Hand rails, now I can position to any degree needed for any type of fishing I do.
Hope this helps,