I uploaded the following manuals today:
TM 11-5820-401-20-1, Organizational Maintenance, VRC-12 radio series
TM 11-5820-401-10-1-HR, Handreceipt Manual, VRC-12 radio series
TB 11-5820-890-20-77, Installation Instructions for SINGCARS radios in CUCV
Once they are approved and available I think you'll find the answers to most of your questions. If you have a specific one that isn't covered, let me know.
I also have the installation instructions for the CUCV radio antennas, but haven't had time to scan them. Probably next week.
For some reason LOGSA changed their format, and all the technical manuals that were listed, aren't available at this time. I'm retired Army and couldn't find anyway to get in to the interesting stuff. Reorganization, or security?