I know this is way later and doesn't really matter, but I really liked your idea and thought about it for a while.

I ended up coming up with this spring "quick caps" for quickly moving, rearranging, or de-tensioning them for maintenance and it has really improved how the whole boom operates.

Anyway, thanks for the idea!

I greased the captured post that it spins around and I've only almost hit myself with it a couple times.

Weirdly enough, yes and no.

I assumed you were linking this video: https://youtu.be/p68Y1e4acF4?si=vS-Dpx9isLgJdFHX

Which is where I thought I was pulling inspiration from, though I'm sure I watched his gantry video and had it sitting somewhere in my mind. I totally forgot he did basically the same thing hahaha.

I also ripped off took inspiration from Inheritance Machining's: https://www.youtube.com/watch?v=t1sXvMY_vAw

And a smaller YouTuber I was talking to had a small series doing some things with 3d printed camera arms: https://www.youtube.com/watch?v=fble2ifR0NI&list=PLNQ9UrHMNMNhJP1yVZK1tsiatytQrkfFw

Just manual, it only needs to be moved into position and remain there for my purposes.

But I have been tinkering with a camera slide made from almost all 3d printed parts that will be motorized (when I get around to it lol)

There's some pretty good gas spring monitor arms, I use a few at my desk. The one I use for a fairly heavy 27inch monitor might fit your use case but they can get pricey. https://www.ergotron.com/en-us/products/product-details/45-241#?color=polished aluminum&attachment option=2-Piece Clamp

The springs I used here might be a bit weak for a monitor, I think the long ones are four pounders. But I don't know much about springs and I just got ones that looked right from Lowes :)

As far as tips from this build, being able to change configurations and adjust positions did a lot to shore up the gap between what I wanted to do and how little I knew about any of this. Also, I'd probably do a 90 degree bend at the middle link.

The rods are 3/8ths inch and the bolts are 1/4 20 hardware, plus 4mm machine screws assembling smaller parts and as grub screws. I think it'll stay together fine, but there's enough load over a long distance that it does have a little sway and bounce after moving it. Although, after a few seconds it settles and I haven't had any issues. I figure that my phone's video stabilization will filter out the small stuff.

Oh yeah, and I printed the components with an 0.8mm nozzle and 0.5mm layer height. They're chonky.

Originally I was using all four, but after working with it a bit and changing the springs orientations I found it worked well with just the one set. I've left the other two in case I change my mind :)

Now you've got me thinking of some sort of quick release system for switching these in case I do want the lean direction to change..... That would be super useful.