A bit unrelated to the actual discussion, but what you say about primary and secondary places confirms my observations about AI gunners.
We all know that if you switch to a gunner position the AI no longer mans the turret. Flying a Blenheim on ATAG one night, i happened to find out completely by chance that if your aircraft has a bombardier position you can give back gun control to the AI: simply cycle between pilot and bombardier once and your gunners will revert to AI control.
This was also reflected on the net stats overlay, where next to my nickname i could see "pilot, gunner" initially and "pilot, bombardier" after cycling positions.
Thanks for confirming my suspicions