batting cutting tip for quilt as you go.
I agree with the suggestions of butting the batting together. A way to ensure that they match well before you zig zag them is to place side by side with them overlapping so that they are exactly lined up, and then cut them with the rotary cutter. This way the cuts will exactly match when you pull away the excess. You can lie them next to each other and they will fit snuggly to zig zag. All the best with this