Helen,

I like the light mediums John Pearse on my 0021. The action is pretty comfortable.

Django Reinhardt used light gauge strings on a longer neck scale which also influences
dynamics. They worked on his particular small round hole style Selmer.

A lot has to do with musical style. I use light mediums to cut through a rhythm section when playing hard with a flat pick. I don't like any of the pickups I have heard so I am experimenting with different mics. The mics inside of the soundhole tend to sound
boxy to me. I think that the guitar was constructed to be heard in front of it, not inside.
If it's a nice guitar, a good condenser mic should bring out the natural tone. Playing
through different amps is a mixed bag. I think a good P.A. system is best. Rare Earth
has put out a portable one for acoustic guitar.

The most important aspect of the strings for me is the balance of the tone. My 0021 is evenly distributed with the Pearse strings so that it's not too shrill or boomy. For this,
I think the 12-58 is the best compromise. Fingerstyle guitar seems to favor lighter gauge strings unless you're a thumper like Big Bill or Leadbelly.

Guitar action should always be comfortable and not have the strings be shredding
your callouses. This is a function of the strength of the fingers and hand as well.
B.B.King and Jeff Beck may be able to bend wires but for most of us, not having to
work that hard is better. A good luthier can set up the appropriate action for a specific
guitar.

Much of this is subjective. How does it feel and how does it sound to you?
What venues are you playing? What sounds good in the living room may not work
on stage. There are so many variables with the action of an instrument and you
really have to explore uncharted territory yourself and find what works for you.
But the good news is that there are a lot of possibilities.

Frank