Always do a surprise inspection and not by appointment. Most centres will allow you to leave your child in the appropriate room and go for a walk around by yourself. This gives you a chance to meet everyone and peek in on your little one too.
I still have anxious moments including guilt and my DD has been going to care for 2 years.
Good luck with your choice it is a really hard thing to do but 2 days p/w wont hurt her. Infact the other days you do spend together you can make more precious.
K