The best way to take on a superior ship like the Pegasus would be to fire first and try and take out the engines. It would be my hope to knock out the power to the ship so that it wouldn't be able to fight, leaving them no choice but to surrender. Which is along the same lines of what you've stated in a previous post.
Maybe bring the Galactica in close behind the Peggy, right on top of the engine section, where there are no gun batteries, and just keep bashing until they lose power.
Bear in mind I would be trying not to destroy the Peggy completely; it would be a big advantage to the Rag Tag Fleet to keep this monster in the ranks.
I've been working on the Pegasus model kit by Moebius for the past week, so I've had this ship a lot on the brain, lately.