I have the Sonic Research ST200, not the ideal candidate for bright overhead sun gigs. So I have Planet Waves NS Micro tuners on all my headstocks, only problematic headstock is PRS because of the design, in all others it sits behind stealthily and cr2032 cells are lasting very long in some of these but not so in others, not sure whats up with that but they do last sufficiently long for me.
The other tuner option I have is in my Boss GT10 itself or the Zoom G1on.
I wonder if theres an app on a smart watch available yet for tuning