That's wonderful your going to help her hatch! I'm guessing she'll have tons of great hatching tips for you

. I've only got one year experience with hatching call ducks! I do 99.5 temp and 55 humidity. My calls are pet quality so most have long enough beaks to hatch well, but I have had a couple that struggled.
I handle them just like any hatching egg. When hatch approaches, I candle daily and watch for the internal pip. Once you see that little beaks popped out of the membrane, give them time to make the external pip. It can take 24 hours. With the call eggs I tend to hover still...so if the internal movement is slowing I make a safety hole...just a small hole near the beak to let some air in. They should have little beak movements almost all the time...if the beaks not moving much is when I do safety holes. Then give them about 24 hours from there to unzip. If they haven't started unzipping, then start removing shell near the beak going up towards the big end of the egg. Go slowly and remove a little at a time. Stop if there's the slightest bit of bleeding and give them more time.
Most eggs will hatch best with no interference. Experience and frequent candling during hatch to get a feel for the natural progression and timing of hatching will be your best teachers. Just don't chill the eggs too bad trying to see what's going on in there. Once you have a feel for a natural hatch, that's when I'd start trying to assist as needed. Always give as little assistance as needed, then give the chick a chance to make it out on its own. Always try to keep the timing as close to natural as possible too.
You'll do good I'm sure. Watching the progression of a hatch is always such a pleasure.