Switching Lights . . . Best way to do it?

[Enigma]

My T5s are about ready to be replaced in the next couple of months. I've been humming and hawing over what I'd like to do for LEDs for this system (36x18x16). I finally gave up on my indecision and just ordered two AI Sol Blues from Modular LED.

I purchased the EXT rail and hanging kit for them, as well as the AquaIlluminations to VDM Adapter Cable (to hook them up to my Apex, so I can dim and control them).

The tank has four ATi 36" T5 bulbs (2 blue+, 1 purple+, 1 coral+) which sit on top of it, and I'm running a 12 hour light cycle (to compensate for the fact that the tank really does need 6 T5s at the least with my covers). It is mostly LPS, with some softies and SPS (which need more light than what they're getting).

Should I just start by running a ramping program and mounting the two Sol fixtures really high and slowly lowering them?

The T5s are total of 156W. The LEDs are a total of 48W. Any ideas as to how the two compare: would 156W of t5s be less PAR than 48W of LEDs driven at 100%?