Using the Ergotron LX Vertical Stacking Dual Monitor Arm. Very sturdy and has worked great!
Ergotron – LX Vertical Stacking Dual Monitor Arm, VESA Desk Mount – for 2 Monitors Up to 40 Inches, 7 to 20 lbs Each – Tall Pole, Polished Aluminum https://www.amazon.com/dp/B07514G4ZL/ref=cm_sw_r_apan_glt_i_DS5BXDFBYKQ0Y578YQMW
I use this one with the 23 inch pole. expensive but it's the only one I could find that mounts at the heights I like
Ergotron – LX Vertical Stacking Dual Monitor Arm, VESA Desk Mount – for 2 Monitors Up to 40 Inches, 7 to 20 lbs Each – Tall Pole, Polished Aluminum https://www.amazon.com/dp/B07514G4ZL/ref=cm_sw_r_cp_api_glt_fabc_D16F6Q1Z760RWDN3XCPR?_encoding=UTF8&psc=1
If you're planning to have them stacked on top of each other, I found the ergotron is the only one with a center pole long enough to do a vertical stack. I personally use the 23" pole.
Oh, my bad. I was referring to the Ergotron LX Dual stacking arms. This link should be correct: https://www.amazon.com/Ergotron-45-549-026-Dual-Stacking-Bright/dp/B07514G4ZL/ref=sr_1_2?dchild=1&keywords=ergotron+dual+stand&qid=1598562837&s=office-products&sr=1-2
Yea I actually love it. It was recommended to me after commenting on my wants in a mount on another post. Finally pulled the trigger and couldn't be happier. I can send you picks of my layout if you want to see. The top monitor is curved and the mount provides just enough downward pitch to accomodate the config.
https://www.amazon.com/dp/B07514G4ZL?ref=ppx_pop_mob_ap_share
I have the Asus version of your 34in monitor. I went with an Asus 27inch 2.5k for the second monitor. I downgraded the monitor resolution to 1080 as I only use it for discord, web searches and etc.
The monitor arm and rod I purchased is as follows:
Ergotron 45-549-026 Lx Dual Stacking Arm Tall Pole Bright https://www.amazon.com/dp/B07514G4ZL/ref=cm_sw_r_cp_api_55x0Bb9T44HCC
It’s pricy, but works great.
Actually no I haven't. https://www.amazon.com/Ergotron-45-549-026-Dual-Stacking-Bright/dp/B07514G4ZL/ref=sr_1_15?ie=UTF8&qid=1532751976&sr=8-15&keywords=ergotron+lx
Amazon for under$300 I found an open box on eBay for $175 well Worth it.
I bought an Ergotron LX Dual Stacking Monitor Arm, Tall Pole but I am going to return it as you can only tilt 5 degrees downwards. It is just not enough downward tilt for the upper monitor. I think with some modifications and washers, I could get it to tilt more. Additionally, while the mount is quality, it just doesn't adjust as smoothly as I'd expect a $350 mount to.
I've ordered a VIVO Single Monitor Desk Mount, Extra Tall and I plan to use a second arm from a VIVO Single Monitor Desk Mount. I chose two combine these two together as the middle link in each arm is double jointed, so you have more mobility than an alternative like the VIVO Extra Tall Vertically Stacked Dual Monitor Desk Mount Stand with 39 inch Stand-up Pole. My two mounts together will also be 31" tall instead of 39" tall which is just taller than I need.
Now... these mounts don't arrive until tomorrow, so I'll see if they work well then. If they don't work I'm not sure what I'll do.
Here is the list if your running 12 x 4k monitors without much video intensive tasks
https://pcpartpicker.com/list/yQN8Kp
Here is the list if you only plan to run 8 monitors ( but with RTX capabilities, up to 8k res, intensive tasks. The Quadro rtx5000 allows for nvlink which combines the two gpu cards bandwidth into one. Thus utilizing more power for a single task) More expensive but better future proof and compatibility.
https://pcpartpicker.com/list/W43LDq
If you want good monitors get from dell, there new 4k monitors...both in 27inch and 32
If you want good monitor arms...Ergotron makes solid ones
Here is the list if your running 12 x 4k monitors without much video intensive tasks
https://pcpartpicker.com/list/yQN8Kp
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Here is the list if your only plan to run 8 video cards (with RTX capabilities, 8k res, intensive tasks. The Quadro rtx5000 allows for nvlink which combines the two gpu cards bandwith into one. Thus utilizing more power for a single task) More expensive but better future proof and compatibility.
https://pcpartpicker.com/list/4WC7hk
​
If you want good monitors get from dell, there new 4k monitors...both in 27inch and 32
​
If you want good monitor arms...Ergotron makes solid ones
Ergotron LX Dual Stacking Monitor Arm, 23-Inch Pole, Polished Aluminum https://www.amazon.com/dp/B07514G4ZL/ref=cm_sw_r_apan_glt_fabc_G4E4WQ1G8A6WXGWTTPMG?_encoding=UTF8&psc=1
Ergotron LX Dual Stacking Monitor Arm, 23-Inch Pole, Polished Aluminum https://www.amazon.com/dp/B07514G4ZL/ref=cm_sw_r_cp_api_glt_fabc_E12S5SYXZ1P38S6H1PTG?psc=1
I've use Ergotron and they are amazing. Here is the dual (one on top of another) setup: https://www.amazon.com/Ergotron-45-549-026-Dual-Stacking-Bright/dp/B07514G4ZL/ref=pd_di_sccai_3?pd_rd_w=fwqQG&pf_rd_p=c9443270-b914-4430-a90b-72e3e7e784e0&pf_rd_r=5PE2D5TJ6KR0WQQRH9F2&pd_rd_r=5312c8dd-6d45-4afa-9807-859b161e571b&pd_rd_wg=bfOB3&pd_rd_i=B07514G4ZL&psc=1
It's an Ergotron LX Dual Stacked Tall Pole: http://imgur.com/a/lMGwJqV
https://www.amazon.com/dp/B07514G4ZL/ref=cm_sw_r_cp_awdb_imm_t1_SbJbGbGH978K4
Using an Ergotron mount. Tried a much cheaper one first, but the monitors would just tilt down under their own weight.
Ergottron Dual Stacking - I have this with a 38 and a 34 on it and it's very stable. Definitely recommend. This looks to be the single monitor version.
I have this one in brush silver and black, it's very well made, and aesthetically pleasing. Worth the cost imo.
It's also cheaper on Amazon:
https://www.amazon.com/gp/product/B07514G4ZL/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1