I got that ruler set when it was on sale too. I love having the different size squares.
As for batting: I am a Warm Company girl which means I use warm and natural, warm and white, and recently warm blend cotton/poly 50/50 (it is available at Joann too) Those batts are predictable, easy to needle, easy to handle, and great in the wash. They can also be quilted further apart than some of the 100% cottons.
You may want to use your old rotary cutter to cut the batting and the QAYG squares. Batting dulls the blade quickly.