Just a quick thought on the small "Font Display Size" issues.
If a software is in use that has not been updated to work with 4K Resolution, would it not be of use to use the original monitor to work with the 4K monitor in a Dual Display set up. The Font would then legible on the original screen and commands can be enabled as well.
That's what I do with Fastone Viewer.
I set it to open on the HD screen, and just use it there.
I don't use CNX-D much(it's a god awful program, and even with a new faster PC, it's still a glacial slug, that seems to bog down the PC!) .. anyhow, I just put up with it on the 4K. I can feel my way through it, and it's nice to have all that real estate for the actual images. I haven't yet looked at using any dual monitor capability if it has that ability.
VNX2 and CNX2 do tho .. just never thought to use them that way(yet). Image on the 4K and tool pallete on the HD screen.
thanks for the reminder.
EDIT: that works well enough for CNX-D