Mind sharing the source of the ballast you found?
The T6 bulbs I have been 2XOD are the 6500-6700K bulbs I use on my planted tanks. I am happy with them.
Unfortunately I have not tried the actinic T6 bulbs, the LFS I mentioned before is using them however on regular 54W T5 ballasts. Plus I have yet to try using a dedicated T5 ballast overdriving the T6 bulbs. I've been using the workhorse ballasts and T8 ballasts for the most part due to the difference in cost, however sounds like you just found a better deal than I have been able to find. T5 ballasts usually run at higher frequencies too so there may some differences when overdriving the bulbs with it, but it's worth a shot for $13. If you can, try it on an old T5 or T6 bulb first, some don't handle it as well as others, if you see flickering/sparking inside the tube near the endcaps, the filament is being burned out and bulb is toast. Another good option I've used in the past are 96W PC ballasts, these are close enough to 110W to call them nearly 2x on a 55W HO bulb and the nice thing is you don't need two circuits. Heat is also a little lower and the light output seems "close enough".
One thing worth noting is that ballasts usually run multiple circuits internally to run several bulbs. For example a 4x32W T8 ballast usually contains two independant circuits internally, each supplying power to two bulbs. Hence the pair of red and pair of blue wires. When combining feeds to overpower a bulb, I have always made it a rule for myself to combine only feeds from the one circuit. Therefore I never combine a red and blue lead. I haven't tried combining different circuits because my gut feeling tells me it may cause problems for some ballasts. For the same reason when I'm buying a ballast for two bulbs I always check that the two feeds are color coded the same, this usually indicates they are being fed by the same circuit. I would also not suggest combining feeds from two separate ballasts. It's been a while since I burned out a ballast but when magnetics were the norm I certainly killed my fair share playing around with this stuff.
Oh, last thing, some ballasts have protection circuits which help avoid overcurrent and detect when a bulb has reached it's end of life. These ballasts may refuse to overpower the bulbs so try to stick to "dumber" technology. I would imagine that some T5 ballasts are also using such technology.
Hope that helps, let me know where you're getting the ballasts from as my new tank arrives today and I'm planning on doing something similar with the actinic T6 bulbs.
