You're never really going to know until you go try some climbs like that. People react to altitude in different ways, and some won't be bothered by 10,000 feet, while others wilt at much lower heights.
Your idea of a 34x32 low gear is good. I've climbed in the Sierra Nevada with a 30x28 low and I'm fat and old.
Stay within yourself, be sure to eat and drink enough, and be as prepared as you can.