Having recently returned from a holiday in Ethiopia, I can highly recommend Girmay Tewelde for anyone interested in visiting the rock-hewn churches in Tigray.
He's a nice, friendly guide, he knows a lot about the history, and can suggest different churches to visit depending on how much time you have and how much climbing you are willing to do. He took me up to Abune Yemata Guh - which was amazing - and got me down safely!
His contact details are firstname.lastname@example.org and +251914108651. I'm happy to answer any questions you may have - please send me a private message.