Brian

We like using the 1.5" ball Ram mounts. I've bought all from gpscity.com so far. We have some mounts with the 4" and some w/8" arms. Everything is pretty heavy duty & they'll hold up a planter monitor just fine. You can get a couple extra balls & then use the arm or base end (tractor) for other Ram 1.5" applications. When you crank that wing nut down on the arm, nothing is going to move. It's solid. I use a 1.5" ball w/4" arm to hold up an Insight monitor & I'm sure that's heavier than most monitors.

We also use a 1" ball in a few cases, but that would be for something much lighter (I think) than a monitor.

We get pretty good service from gps city. Maybe there's somewhere else cheaper & better, I don't know it.

Here's a link to gpscity.com 1.5" ball products:

http://www.gpscity.com/ram-1.5-c-ball-parts.htm

Here's the RAM company web page. They have a couple of very long catalogs you can download via pdf. I do not think they sell direct:

http://www.ram-mount.com/

This is photo from OUTside the cab-looking in on Inisght mount

Our grain cart scale is mounted in JD8420 via Ram 1.5" ball