Last update on this thread;

I did a gig last night with the band and used the "sweetened" tuning on two acoustic guitars.
There's no doubt that there is a benefit in using this function but I'd be exaggerating if I said it was anything more than marginal. When using a capo at different points of the neck the Peterson tuner offers a sweetened tuning option for each position but that's hardly practical in a gig situation.
That said, any improvement is a positive, and the tuner is by far the best of it's kind (clip on) that I've ever owned, so I'm happy with the purchase.
I could still hear some occasional disparity between the violin and my guitar but maybe I'm a little too focussed on the problem and listening for it. In addition, you only have to strike a string a little hard to get it to sound sharp and then there's capo-placement, etc, etc, so I might be chasing shadows.
In conclusion, it's good piece of kit but it won't make you(me) a better player!
C-flat