Oh Holly she's looking great! And I agree with the others - I dont think you will have much longer to wait to see this (pinto) baby! The main thing to remember with a possible red bag delivery is that you need to get baby out fast. Hopefully as soon as you carefully split the red bag you will see baby right there inside the following white 'bubble' and approaching in the right position. This is the time to grab baby's legs and to help/assist it on a speedy delivery - not actually pulling, but keeping the pressure there to easy it out with each of the mare's contractions, and whip the bag off the baby's head as soon as the chest is delivered. Remember that once true labour starts and the placenta separates, baby has lost its oxygen supplies until birth has taken place, so as fast a delivery as possible is vital!
I'm sure everything will be fine, she's a great mare for breeding, especially to a smaller stallion, and you are doing the right thing by keeping such a close eye on her. Cant wait to see this very special foal after all that you and she have been through.
Good luck!!