Will,
1) As you've undoubtedly gathered by now, there are "personal preference" and "application specific" factors that are heavily in play here!

But, in general, I (and most) would find the front panel of a radio set-back 24" from the front of the desk to be too far.... 12" to 16" is more standard.
Please read what Peter wrote here....it is very good:
My TRX is 15 inches (40 cm) off the edge of the table. The TRX directly on the table top and not elevated so that I can rest the arm on the table and I can operate the VFO comfortably with my hand without fatigue.
I see a lot of shack pictures where the radio is higher and the arm has to be in the air to operate the VFO. Or the TRX is behind the PC keyboard and you can't rest your arm on the table because of that. You can't do fatigue-free operating with such arrangements.
For right-handers, the TRX must be on the right, unless you are doing CW with your right hand and want to operate the TRX with your left hand at the same time.
73, Peter - HB9PJT
2) In addition to personal preference / application specific criteria, shack ergonomics is also dependent on your rig! Some rigs are very good in this regard, allowing you to easily operate them and their most often used controls....and mostly with your dominant hand, with your forearm resting on the desk...
Please have a look here at this thread, where you'll find some examples of great rig ergonomics (and examples of some with poor ergonomics, too)...
https://www.eham.net/community/smf/index.php/topic,128776.msg1275560.html#msg1275560 https://forums.qrz.com/index.php?threads/radio-front-panel-layouts.833074/page-33) And, directly to your specific questions....
On my primary operating desk (at home), I do have my rigs set back a ways farther than some other hams, at about 15" - 16"...this gives room to have a full-size note pad (8.5" x 12"), as well as CW paddles and/or a desk mic base, etc., without stuff hanging over the desk....
{And, if using a standard 30" width table (or door) this allows 14" - 15" of depth for the rigs/accessories (actually, a bit less, to account for a rear-edge grounding/bonding strap/buss bar)....and, if placing this 4" - 6" away from the wall (for both good air-flow and allow easy-peasy cabling access, etc.) this doesn't take up too much room.}
Have a look here:

At my temporary QTH, I'm very limited in space, etc....so my rig/speaker/accessories are on a night-stand, and only 3 to 4 inches back from the front....with my amp, wattmeter, scope, analyzers, etc. in the adjacent closet...
Have a look here:
Bottom line, 24" is a bit of a reach....but, "how far" depends on your rig, your actual application, your accessories, etc., and your operating style...
(some hams feel they need a computer/monitor in front of them just to use their radio / make contacts ---- heck some even need the internet to use their rigs/make contacts....others feel even solid-state devices aren't needed....most of us fall in the middle...hi hi)
I do hope this helps?
73,
John, KA4WJA