Cuda,
I've have been thinking about your comments and other opinions about the 20K+. I use 150W Ushio 20K+ double ended in some fixtures for aquaculture. It just gives me certain colors I don't get using other bulbs. In my personal display and ones I set up for others I always use combination fixtures. However I would not run Ushio 20k+ with all actinic. In most cases this would result in a dark looking blue deepwater tank. Of coarse using high wattage and small tanks would minimize this effect. Personally I don't like all my corals to have a blue cast to them. I prefer representing a shallower reef area. From personal communication I know you're running 4 - 96W PC bulbs with your 2 - 250W Ushios. FWIW if that were my tank I would run 2 actinic and 2 actinic/white PC's. This would maintain a lot of the blue which make some corals pop while the whiter spectrum will add brightness and more color to the other corals.
Just like all Kelvin ratings over 65K the 20K bulbs vary quite a lot in color and intensity. However with the set up you have you should be able to dial in the color your looking for using your PC bulbs. I would never give up on a new MH bulb after a few weeks. I hope this helps. I will work on putting together a MH buying guide.