I don't know your situation, but if you already purchased the Studio Display with the regular stand (or height adjustable one), you can't add the VESA mount after the fact (at least not without taking it to an Apple Store and paying them to do it).
The gap between the desk and display is dependent on which VESA stand you purchase... every brand comes with varying height adjustments.
I recently purchased this one on Amazon for my 34" LG Ultrawide 5k and it works fantastic (even though the clamp versions are more easily adjustable, I didn't want a clamp damaging my wood desk top).
As an Amazon Associate, MacRumors earns a commission from qualifying purchases made through links in this post.
The VESA mount has to be purchased at the time of buying your monitor. It's not a user-installable option. Same with the two different stand options (tilt, or height-tilt).
You can take your ASD to an Apple Store and have them disassemble the display and change out the stand or replace it with a VESA mount or different stand, but expect to spend about $200-$400 (service cost + price of stand).
Unfortunately, the mounting bolts for the stand/VESA connector can only be accessed from the inside of the display, which means removing the glass and LCD itself to access it.
I bought two VESA models so I'd have flexibility. The height/tilt stand is gorgeous, but I knew I might want one in portrait (which is how I have one), so best option for me was the VESA models.
And yes, it does support rotation sensing and macOS will automatically adjust the image and camera orientation when rotated.
Elevate your monitor to a comfortable viewing height with the Single Monitor Desk Stand (STAND-V001H) from VIVO! Constructed of high-grade steel, this stand was built to resist scratches and support monitor screens weighing up to 22 pounds. The modern appearance blends well with many home and off...
www.amazon.com
As an Amazon Associate, MacRumors earns a commission from qualifying purchases made through links in this post.