If you are getting scalloping or weird artifacts on the wall due to the reflector design of MR16's, I suggest you use a "soft focus" filter. It will smooth the beam quite nicely. These are included accessories on my favorite downlights (IRIS), and I have had great luck with them. If you don't have the room for a filter in your fixure, check out Ushio's line of lamps called the Superline, or the softline series. (
http://www.ushio.com/categ_gl_halogen_ref.htm)
Good luck!
