Pulling a really long mane?

Today I'm going out to the barn to get a horse ready for the clinic I'm taking her to tomorrow. Lately it's been really warm where we live so she sweats a lot under a her mane. She look silly in a running braid, and she still gets sweaty with it. Her mane is pretty thin, so I don't need to thin it. Do you think I should cut it a little then pull it? Also, how long do you think I should leave it(inch wise)? Thanks!