I don't know the difference between regular glue and felt glue, but I have good luck with tacky glue. I usually use only a small amount to hold it in place while I machine or hand stitch it down.
I felt my own wool also. I ask friends and family to save wool garments and then wash in HOT water and dry in HOT dryer. If they are going to fade they do it then not after a project is completed. Here are a couple I have done in the last month or so.