I suppose, 250s would be bright enough if you went with a more 10,000K-ish bulb. G-man 14,500Ks or something like that. Just depends on the specific bulb more. If you go with a more daylight bulb though, I can see you wanting to add on a couple rows of 54watt T5s with blue bulbs though to even things out. I suppose what I am trying to say is that there is no 'happy medium' with halide bulbs that I have ever found. They are either blue as all heck, with almost all the daylight removed... or they are daylight, and with a good amount of yellow.
There is also the 'reverse supplimentation' possiblity. Usually, its not as efficient, since halides are better at daylight, and T5s better at blue, but you can suppliment a bluer bulb with a couple strips of T5 daylight bulbs to even things out. Sometimes, just one row of T5s like this is enough to bring up the daylight to a reasonable level, and since the outputs of many bluer halide bulbs are getting pretty high, the efficiency isnt so bad.
Overall, Calfo is pretty dead on with his summary of 250's and 400's. Usually, 400's are overkill... but it always depends on the specific bulbs. If you were to use Ushio 20,000Ks for instance... you would have less output than many 250w 10,000Ks. But overall, compared to say.... lighting systems that were out there 8-10 years ago (see Rick Boyd), efficiencies have improved the output of the bulbs by at least double. So people that were using 400's back then may only need 250's now... with the better reflectors like lumenarcs, higher efficiency bulbs and ballasts, etc. Yet many people still base their suggestions for lighting on what was out 8 years ago! 400's still have their place... and maybe even on your tank. There are plenty of SPS tanks that people have set up with your wattage and configuration/reflectors. They might use Radiums or even Aquaconnects, and the corals are colored in very intense.
Honestly, I like gopack's setup.... very efficient... but I think in the long run he will either have to drop his light rack down 4-6" or get better reflectors (using hamilton reefstars) because he just doesnt have those 'peak levels' towards the top that some SPS will like. Some SPS live being under light in the 400 range. I have a pink w/ blue tip milli that wont color in unless its under 350-450 light levels. He pretty much knows that new reflectors are something on the shopping list.
My favorite configuration for bulbs is along gopack's setup though. I like the ushio 10,000K/14,000Ks with T5s supplimenting the actinic/blue range at about a 2:1 halide to T5 ratio. Those halides dont really even need actinic, so if you just go with blue (ATI blue+) T5s, the ratio can be more like 3:1 or 4:1. Its a nice full range light (not monochromatic blue like a pheonix bulb or somewhat like the Reeflux bulbs you currently are using), but with enough blue added back in to please the eye.
You could do something like 4x250wattDE/HQI bulbs, with ushio or Giesemann 14,500K bulbs, and add 8x54wattT5s for blue. The thing is, in the end, you will most likely end up with even more light for a couple hundred less watts. The 10,000K 250's may rival your current bluer bulbs in output as it is, and then adding the T5s on makes them even more potent. So I wonder.... is it really worth stepping down in your case? For 400s on up, 20,000Kish bulbs have pretty decent outputs compared to more daylight bulbs. Some of the highest output 400's are 20,000Kish bulbs.. Aquaconnect 14,000Ks being a prime example of a blue monster. And because their output is so high, they actually tend to have a pretty decent amount of daylight built in... you just cant see it with the huge blue spike. I know there are people who have lighting similar to yours (reflector, wattage/output, color) with great results w/ SPS.
Its hard to say what to do in your spot. If it were me, Id just wait and see how things work out with your current lighting. Its really not 'too much' as long as you acclimate your corals better. I can see the aspiration to lower the heat output, but I cant see that happening w/o removing your existing ballasts AND reflectors. If you step down to 250's, I would strongly suggest going with DE bulbs over SE... and that means different reflectors (unless you send them in to PGS to have them retrofitted with DE sockets and sheilds... which I have seen).
