= ASTRON Rex Closest American Medium Crew Layout and Crew Skills =
The tier 8 ASTRON Rex, as a premium vehicle, is not a good crew trainer. Its crew layout is completely unique to the American mediums with three crew members and an overtasked commander and gunner. Of all the American mediums, the closest crew layout is the T2 Medium Tank, a Tier 2 Collector Vehicle. Difference being a more common Commander/Radio Operator crew seat instead of the ASTRON Rex’s unique Commander/Radio Operator/ Loader seat. It’s worth emphasizing, the only other American Medium in the game with a Gunner/Loader seat is the T2 Medium Tank.
Loader crew skills functionality is debatable on a vehicle like the ASTRON Rex. Intuition and Adrenalin Rush have circumstantial use due to the ASTRON Rex’s small ammo capacity, combine with the between clip reload time. It’s more practical to carry only AP and APCR instead of HE, and its not a wise strategy to deliberately reduce your hit points to gain inter-clip reload. Safe Stowage is never a bad idea but deserves a low prioritization due to more desirable Gunner or Commander/Radio Operator crew skills; see Deadeye, Recon and Situational Awareness.
Alternatively, there are a couple American mediums with Commander/Radio Operator seats, but most are premium vehicles, defeating deliberate vehicle assignments. Only the T69, Tier 8 Tech Tree vehicle, has a Commander/Radio Operator seat. Of other note are the Loader/Radio Operator seats in the M60 & M48A5 Patton. But use in this application this would require retraining to a commander, defeating the purpose of a crew trainer.
ASTRON Rex Crew:
Commander/Radio Operator/ Loader
T2 Medium Tank Crew:
American Medium Tanks with a Commander/Radio Operator
T69 (Tier 8 Tech Tree)
T42 (Tier 8 Premium)
TL-1 LPC (Tier 8 Premium)
T95E6 (Tier 10 Premium)
TL;DR: ASTRON Rex is a bad crew trainer unless you want to pump up your T2 Medium Tank crew or your T69 commander.