I had my HDS-10 on the Ram swing arm mounted to the side. That worked great.  It was a whole lot heavier than these Garmin's.

 

 

I have a Solix 10 at the console and a Solix 15 up front.  RAM makes a ball that mounts directly to the back of the Solix and this arrangement has worked well for me using the D size mounts.

I have a 9 inch screen so it stays screwed into the dashboard 24-7

A 9" in the console.   How'd you pull that one off.  I had to make a whole new face plate for my dash to rearrange gauges and do away with the speedometer to mount a HDS-5 in it.  I was running the HDS-7 on the bow, the HDS-5 in the console, and HDS-10 on a swing arm all networked together.

31 minutes ago, Way2slow said:

A 9" in the console.   How'd you pull that one off.  I had to make a whole new face plate for my dash to rearrange gauges and do away with the speedometer to mount a HDS-5 in it.  I was running the HDS-7 on the bow, the HDS-5 in the console, and HDS-10 on a swing arm all networked together.

Well, remember that I am a cheapskate with little skill. I just ran 4 screws into the console. I guess I should say it’s on the dashboard, not in it. And it’s not a humminbird like the OP was asking about 

19 hours ago, MN Fisher said:

Are you using 'B' size (1") on those Rams? If you are, moving up to 'D' size (2.5") might fix the problem.

To get the D size to hold I lined the sockets with grip tape and crank the living beejesus out of the crank handle with a wrench.  Have to tighten it 3 times in a row with some space to let the plastic settle.  When I take them off there are huge grooves in the balls.  Any less tension and they creep.

 

I 'need' the flexibility of moving the mounts.  I like them really high for scouting and bass fishing, but if I am going to pull lindy rigs for some shore lunch I want them down low so my rod can be over them.  Contemplating the balzout and a few others.  I will start a thread here in the next week or so as I narrow down the options.

16 hours ago, Way2slow said:

I had my HDS-10 on the Ram swing arm mounted to the side. That worked great.  It was a whole lot heavier than these Garmin's.

 

 

The swing arm ram is a different beast.  They hold.  The balls however, not so much.