They do say that less is more :)
AromaWeb has a little section on using reeds to diffuse oils:
http://www.aromaweb.com/recipes/aromatherapy-essential-oils-reed-diffuser-recipes.asplink
Personally, I'd go along with my book, which says to avoid using oils too often. A natural incense or a resin is a good alternative, and then there's a few blends which can be used to deal with odours ~ to be used in a spray bottle with water