Buy a tuner, if for no other reason than it saves time and tunes more accurately. (What other reason do you need?) I can tweak individual strings by ear, but more than that I gotta have the tuner.

I too use the Intellitouch tuner, though there's not an ideal spot to attach it on my old autoharp. I usually attach it to a couple of pegs. Sometimes I'll use a chromatic "guitar" tuner with the built in mic and that works okay, though it's more prone to picking up other strings vibrating in sympathy with the one I'm tuning, if they're not muted.

So long as you can get a chromatic tuner, you'll be okay.

Mooh.