I have contacted the two guides you recommend in Cortona and Siena. Whom do you recommend in Assisi?
Try Ann's Italy dot com. annsitaly.com, I don't think she has an "e" on the end of her name. We were going to use her but we will not be going to Assisi this time.
She is from the US but has lived with her Italian husband and family in Italy for some time. It's all on her website. She does just about everything, cooking, group tours, individual tours etc...
If the website doesn't work, google tours in Assisi or her name. Hope this helps.
We have taken two tours with Anne Robichaud and I am pretty sure she has an "e" on the end of her name. She is fantastic and I highly recommend her. On our last tour with her we had a wonderful wine tasting in Spello and were serenaded by Salvatore. It was one of the highlights of the trip.