I can relate to the issue of satisfying the ear of a fiddler/violinist...
I trained as a piano tuner in UK and now work in California specializing in Steinways...Have used a computer as an aide for about eight years...
The computer gives me an edge over 'ear tuners' as it allows me to stretch octaves consistently and give as near perfect a tuning as is possible...HOWEVER....
this is all equally tempered stuff and fiddlers tune their open strings to pure intervals and fiddlers don't like playing with pianos....I think this parallels your experience in the band...
I would bet your tuner against her ear anyday in a band setting...you're playing a class guitar with factory set intonation....
Don't know what to suggest, apart from having an open discussion in the band, with each member doing some research to reach some conclusions that will, hopefully, back you up....

Good luck...
cheers
Pete