Toward Ecosophy

The ritual as given in The Gnostic Celtic Church is the standard Sphere of Protection as taught in AODA and elsewhere, so you should be fine. (You might consider picking up a copy of The Druid Magic Handbook for more pointers on how to use it.) Yes, you can certainly use it to direct blessings and protections across distance; when I was the head of AODA we several times used the Sphere of Protection to direct healing energies at a member of the order who needed it, and had some remarkable cures as a result.