mama. My DS is a sensitive little person who doesn't like change. Our first transition into daycare was rough and it took a long time before it was all OK (about two months. Gah.)
We learned from that experience and did subsequent transitions much differently: we set a very predictable, consistent schedule and did not do what I did the first time (i.e., rush over and pick him up early as much as possible. It just confused him -- he never knew when I was coming or how long he was going to be there and I think that was hard on him.)
I would ask the daycare providers what they have seen work with children with her general personality. I suspect that they will suggest some version of ripping the bandaid off quickly, and FWIW, our experience with a sensitive kid has taught us that that really is the easiest on everyone. If I were you, at least for the first little while, I would either not peek in until the end of the day or always go at the same time every day. You might also want to talk to them about exactly what they do after you leave -- you could work with them if it doesn't sound right for your DD, or, more likely, it will make you feel better to know that they are cuddling her and engaging her in an activity to help her feel safe and cared for. My last tip is that we found that always handing DS off to the same person was helpful, so if that's an option, that might be something to try.
FWIW, he likes "school" a lot now. Good luck and hang in there! It gets better!