I'm so glad you are having your shawls blessed. I've made many prayer shawls and always take them to my priest for a blessing. He always asks about the recipient and needs and then prays a very special prayer. This means a lot to many people, knowing the prayer, concern, and blessings being extended to them.
If you are familiar with the shawl ministry website, there are many prayers listed. I often use the second one--Prayer of Blessing, by Janet Bristow, 2000. Toward the end, there are also some good ideas for shorter prayers/notes to include with your shawl. The last one I sent to a young mother with cancer, I picked from several ones to custom make something suitable for her. My daughter types and prints them on card stock, and we put it on top of the shawl after it is blessed and before wrapping.
I also understand what Stiney is saying, and of course would approach a shawl enclosure differently in those situations.
Your shawls will mean a lot to the people you are sending them to.