I just sold an on the air ART-13 and ARR-15 receivers for $1k. The ART-13 was complete and virtually new condition. The ATC (Navy designation) and the ART-13, both T-47s, are virtually the same. I would shoot for the easiest one to get on the
air. I might also recommend an a.c. power supply, to begin with. That will allow sequential application of voltages; filaments first, the 400v, then the 1100v HV.
Things to sequentially check:
All tubes light up.
Autotune works and properly "homes". ( no home, no TX key).
Apply 400v and check grid drive.
Finally, apply HV and check for power out.
If you need initial dial settings for test on 75 meters (can provide).
You will need between 700 and 1100pf of loading to tune 75 meters at 50 ohms.
Been there, done that, at least 8 times.... It can be done.
Jeep K3HVG