Run all of your empty jars through the dishwasher prior to using. Alternatively, wash in sink and rinse well.
Get all four of your pots going as described above. Set out a large bowl of ice water as well as another large bowl to hold your peeled peaches. Juice your lemons and set aside.
Four peaches at a time, score the skin on the top and bottom of the peach in the shape of an "x" with a sharp knife and then place in your blanching pot. Allow to sit in the boiling water anywhere from 30 seconds to 3 minutes. Remove them with a slotted spoon when you start to see the skin peeling away. Transfer hot peaches to an ice bath and repeat that process with another four peaches.
Remove the skin from the peaches in the ice bath by pulling at the corners and transfer peeled peaches to large clean bowl. Cover with lemon juice. I typically pour all the lemon juice in at the beginning so that the peeled peaches can roll around in it and keep their vibrant color.
Add half of a vanilla bean to each empty clean jar.
When you have enough peeled peaches to fill 7 of your quart jars (for me that's about 4 peaches per jar, a total of 28), start slicing them up. I like to hold the entire peach in my hand over the peach bowl so that extra juices land back into the bowl and use a small paring knife to cut slices all the way around. Then, once the entire peach is sliced, I transfer them to the jar through the funnel by pulling the slices away from the pit. Fill each jar to the bottom of the rim.
Using a ladle and the funnel in the jar, fill each jar with sugar water. Be sure to leave a good half inch from the top empty. You will need this space in order to get a proper seal. Best practice is to use the plastic air bubble remover wand that came with your canning kit to move the peach slices around to let the air pockets rise to the top. This will let you know if you need to add more liquid.
Once all the jars are filled, use the magnetic wand to pull your clean lid out of the hot water and place it on the top of the jar. Pull a ring out of the hot water and secure it to the jar. You want to screw it on securely but not tight. If its too tight, the air bubbles can't escape and you can't get a good seal. If its too loose, you risk your peaches spilling out. Just nice and hand tight.
Place the 7 full quarts with lids into the boiling water. Either do this one at a time using the jar holder or place them on the round grate and lift them down into the water all at once. Ensure that the jars are covered by at least 1 inch of water. Keep temperature on high and cover with lid. Allow to process in water bath for 22 minutes (this time may vary by elevation and I'm close to sea level). If water starts to boil too rapidly, you may crack lid to allow some steam to escape.
Remove jars and place them on a towel on the countertop. Within about 30 minutes you should start to hear the lids pop meaning that they are vacuum sealed. Allow to cool overnight.
Repeat until all peaches have been used. You may need to make more sugar water if you run out with the ratio of 1:10 sugar:water. With the last batch, I always transfer the lemon/peach juice to the jars before I add the hot sugar water. This changes the color and the flavor, but I love it.
The next day, ensure all of the jars have sealed. You can see the little dip in the lid, otherwise press down and it shouldn't move. If any didn't seal, do not store. Just eat them up.
Remove the rings and soak to remove any stickiness. The rings are not necessary for storage; just the sealed lids. Rinse the jars, taking care not to bump the lids to break the seals. I keep mine stored on shelves under my stairs away from light in steady temperature. Best if used within 6 months but I've eaten them after two years of storage and they were still great.