Hi Glen, good to hear from you again and that you are enjoying and improving your listening room, the panels look very good.
It is very interesting the difference some simple panels/absorbtion material on walls and in corners can make. I have experimented in our lounge (my hifi room) hanging up some blankets against side walls and placing some on corners over old standard lamps in back corners behind me. I measured with REW and listened and there was a marked improvement in definition/clarity. I broached the panel subject with SWMBO (Sue Who Must Be Obeyed), saying I would make my own nice looking ones to blend in, the answer was an emphatic NO!
If you put ceiling panels up I read somewhere that it is best to have them about 2-3 feet in front of the speakers and for them to be suspended about 2-3 inches off the ceiling. So you should only need a couple in your room I think.
Will be interesting to hear how you find it if you do put ceiling ones up.