depends on what you are after..If I was going to use the CM30 with the PA800..I would keep them on the floor[better added bass response]..

If you need the CM30 for a vocal monitor only..then in your face..but over kill with a full range speaker like the Roland[ a waste with just vocals.]..
One CM30 high and the other low would give you a full range, but would not be a great stereo image..

I still prefer the speakers on the floor...tilted if you need the coverage..