Hi Seany et al,
The vast majority of electronic tuners which are available today are for the tempered scale. This scale was used to play J.S. Bachs "Equal Tempered Clavier" in all 12 Major and 12 minor keys. He needed equal temperament so that the tuning was "tolerable" in all keys, that is - equally out of tune in all keys. So trust your ear, the fiddle players can follow, fretted instruments can adjust somewhat and the keyboards can play what suits them. It may be an idea to tune the whistles like the pipes - tune to a drone - whatever key you play in most. Note that the pipes are more in tune if tuned properly than the tuner. Have a listen to a note on accordian they get their vibrato by having two closely tuned reeds. Close enough is good enough.