RDP doesn't connect you to the remote desktop, instead it sends commands forth and back and simulate desktop on your PC using your own videocard, thats why resolution with RDP is your video card dependent, Radmin shows you remote desktop "as is" and resolution is remote video card dependent.
Well I am unsure actually, but it looks like for now it is a single registry key. However you can make an experiment: add AD group to Radmin, export key, remove AD group, repeat with another one, restore first key (so you have 2 keys) and check what happens )
Because this forum is a moderated one. The main purpose of this forum is to assist our users to find solutions for their issues. Some topics become outdated, some answers get their home elsewhere (at example on our support page) e t.c.