I purchased zoo med 50/50 reef sun and aqua-glo. It will arrive on Saturday. I will post my feedback on it
Instead of 50/50 could you theoretically obtain the same lighting with a dual bulb fixture, one 6500k bulb and the other actinic?
That depends on several factors, such as what plants you want to keep, if you're dosing ferts, if you're injecting oxygen, etc. You need to maintain a balance between what looks good for the fish, and what helps to grow the plants.
As for bulb color temperature is concerned, the plants won't utilize light nearly as well outside the 5,000k to 10,000k range. I have found personally, that with 50/50 bulbs or actinic light in my planted tanks, I grow algae much faster, and the plants get no benefit from the light. Others have reported different results. Granted, my 50/50's and actinics have all been Power Compact Fluorescents, as opposed to standard fluorescent T12, T8, T5, or T5HO. I've never messed with halides yet...
I'd recommend a 6,500k & a 10,000k bulb in a 2 bulb fixture. The 6500k is generally agreed upon to be best for plant growth, and the 10,000k should do ok for plants, while helping to cut the red/yellow tones of most 6500k bulbs and bring the blue back to the tank. I found that when using 2 bulbs like that, plant placement aside, that I like having the 10000k bulb in the front socket, to make the colors pop a little more on the side of the fish you get to see.