Can I be a unit administrator for a Reserve unit and drill with a different unit, or do I need to drill and be an UA for the same unit?
It used to be required but not anymore.
I'd had a recommend to go here, I couldn't get it, look also at their online PhD in comp sci (CS)...trust me, submit here also, you won't be wasting your time, I assure you....

Naval Postgraduate School - Wikipedia
The Naval Postgraduate School (NPS) is a graduate school operated by the United States Navy. Located in Monterey, California, it grants master's degrees, engineer's degrees and doctoral degrees. Established in 1909, the school also offers research fellowship opportunities at the postdoctoral level through the National Academies' National Research Council research associateship program.[3]
I didn't know if you'd known you could submit for this, all warrant and commissioned for all svcs, as well as senior MCOs from USAF and maybe other svcs, can, God knows, I'd wanted to go...if you haven't submitted, you really should honest....

Air Force Institute of Technology - Wikipedia
The Air Force Institute of Technology (AFIT) is a graduate school and provider of professional and continuing education for the United States Armed Forces and is part of the United States Air Force. It is located in Ohio at Wright-Patterson Air Force Base, near Dayton. AFIT is a component of the Air University and Air Education and Training Command.
If you're not in this get, trust me, I think you'd find it of interest, honest....