I'm not at all up to date on tuning apps but something tells me a quality tuner pedal might be more precise for setting intonation than apps or clip-ons. This is a procedure where accuracy is pretty important.
Have the Strobostomp on one board and a cheapo on the small board.Peterson has a Strobe Tuner app for $4.99, but looks like only Equal temperament is available - the GTR temperament setting is what makes the Peterson tuners great, so without that I wouldn't bother.
Big time - I had an acoustic rhythm guitarist I used to play with and he was skeptical of my Peterson (I was using the VS-II back then,) until he tried it once using the GTR temperament - after that he wanted to use it every gig - I was finally like, "DUDE - get your own!"Have the Strobostomp on one board and a cheapo on the small board.
I miss the Peterson when it isn't there.
No longer available on the Google Play store, despite Peterson having the "Play" logo on their site.The Peterson Strobe tuner app is the only thing we use for intonation adjustments in our shop. I think it’s $10? It’s much better than any other tuner app.
Honestly it's not necessary to have intonation more precise than your everyday tuning. If you play around with a precise tuner, you'll likely find that some of your frets are a few cents sharp or flat even with the intonation set correctly.
One concept that I've seen (but haven't tried, because it doesn't bother me) is to shift your tuning and intonation into the area most frequently used.It's nice to have a reading in cents. Not really necessary. Honestly it's not necessary to have intonation more precise than your everyday tuning. If you play around with a precise tuner, you'll likely find that some of your frets are a few cents sharp or flat even with the intonation set correctly. That fact does really bother people who are cursed with perfect pitch; for them compensated nuts or "true temper" frets may be helpful.
It IS important to have a tuner where "dead on" is a precise point. Which is the case for most tuner apps. I've used the Gstrings app, it doesn't tell you how many cents but it does have a display down to 0.1 Hz. Which is reasonably close. At the low E string, E2 (82.4 Hz), 0.1Hz = 2 cents. For the high E string (E4, 329.6Hz) 0.1Hz = 1/2 cents. That's plenty close for me, but I don't have perfect pitch.