TUNINGS FOR SESSIONS

I have read Robin Clark's really helpful blog on tunings but I am still not sure what tuning I will need to be in if for example I wanted to play Poor Wayfaring Stranger or other minor tunes with say fiddle and banjo players.

When I normally play this I am in DAC or (as attached) in AAC but I'm not really sure what key I'm playing when playing in AACin or if that is likely to sit OK with Banjo and fiddle ( maybe I should re-read the blog!) but I know it sounds best.

I have tried other set ups such as EAD but they dont seem to sound as good as when the melody string is C as an open string ie DAC or AAC

Can anyone advise?