No need for the number of stitches to match. Just make sure they line up with the beginning and ends at the same place. I usually lay mine out and stick a little hair clip on the middle and the ends. These little hair clips are inexpensive, and work great for holding seams together while you work.
Thank you. Love the little hair clip idea! The little claws really grip the yarn. This forum is so great. Crochet has mostly been a solitary thing for me, but the tips and ideas shared here are just wonderful.