Rod holder question

[Hoytman86]

I'm not planning on using a track system. I was actually looking for something like I've linked below. There are 2 flush-mount rod holders on each side of the boat, I'm going to weld aluminum poles on the bottom of one of each mount to slide down into the existing flush mounts. I know they make gimbal mounts for just this purpose, but they're expensive and I'm trying to keep it to 1 piece per side. I will keep those in mind in case I can't find what I'm looking for. There's certainly enough room on the gunwales for whatever I want to do, just trying to avoid additional holes in the boat if it's at all possible, and want to be able to remove the holders when we're not fishing. The picture below is Cisco's storage racks, but they're around $335 each. I'm sure they'll work for trolling if that's the only option I can find, but I figured I'd check here first to see if anyone knows someone that makes them for less.

Thanks!