Pedal steel tuners – choose one that works for you. Consider tempered tunings, pedalboard/mounting, quality, and price.
If you tune pretty close to straight Equal Temperament (ET), A=440 Hz, like Buddy Emmons did later in his career, the Polytune (below) is a good tuner to use.
You can get a good in-tune sound from your pedal steel if you tune almost like a guitar player does: straight A=440 Hz, for all 10 E9- neck strings, but drop your G#’s by a couple cents (or looking at tuner, have them very slightly flat). Your ear will get used to it over time (if you’re used to tempered tunings), and you ear and muscle memory will compensate with slight bar slanting for different inversions and relative chords. Even with pedals or knee levers depressed.
Since the polytune is a guitar pedal, and doesn’t come factory with any capability of attachment to the pedal steel, I’ve found attaching it to a reliable pedalboard to be the best option. Also, keeping it close enough to comfortably turn on/off with your hands or feet is a must. You must also be able to comfortably view it, and simultaneously tune the keyhead or pedal action. This is one option, with a view from the cockpit.
I find playing with a tempered tuning great at home, or playing solo, but challenging when playing with other instruments, especially keyboards. If everyone on the bandstand is tuning electronically, chances are they’re tuning close to straight ET; and if you do too on steel, chances are you’ll sound more in tune with them. That’s my experience, and I’ve tried both types many times. Nowadays, ET vs. JI seems to be mostly a matter of the player’s personal preference and ears for pedal steel.