I think that's a very sensible option under the circumstances. Thank you.
The reason I made the post is just in case someone somewhere knows of some rulings that I'm not aware of that covers this.
For simplicity I've stuck to RMSS, which is complex enough for a part-timer like me. However, players being players have talked me into using various other bits and bobs, like the spells found in the companions. It's my own fault I should be more strict.