Thanks for all the advice, my LQS had kits of 5 different doggy themed fabrics, 1/2 yard each, in pink or blue. So I thought that would be a great practice starter for me, as ktbb noted the dogs won't care what size they are and even if the seams match, I could also use it for a sampler free motion practice piece.
My biggest problem is that I just didn't know what size the squares need to be cut.