I used side mount, mounts on the side of the gunnel. the two top bolts I used well nuts. they are the rubber encased thread inserts that lock themselves in the hole when tightened. I got them at Fastenal. they do require a larger hole drilled in the gunnel but to me they look more “finished” when your done. and they pretty much seal any water out of the top rail when the mount is tightened down. the lower holes I drilled through the side completely. they ended up being just under the channel and pretty much out of sight. I attached a pic, had the boat for 4 years, and could only find one pic of the rod holder mounts lol. one mount is shown next to my right hip. I also used all stainless hardware. hex head bolts and nylock nuts. had eight on my 08 classic. all were as solid as the day I put them on when I traded it in.