In a pot, bring to a boil the vinegar, water and garlic; simmer on low for 5 minutes, then strain out and discard the garlic.
Add a pinch of Pickle Crisp to each jar (optional).
Divvy the vinegar mixture out amongst the jars, leaving 2 cm (½ inch) headspace for all jar sizes.
If you are short of the vinegar mixture, top up the jars with pure vinegar.
Debubble, adjust headspace.
Wipe jar rims.
Put lids on.
Process in a water bath or steam canner.
Process jars (any of the 3 sizes) for 10 minutes; increase time as needed for your altitude.
Notes
With this quantity of jalapenos, you will want plastic or rubber gloves on, for sure. It's a lot different than just doing one or two peppers.The Pickle Crisp is optional; it just helps to keep the pepper slices firmer.How many seeds you leave is up to you; that's where a lot of the heat is.