I wasn't very actively photographing the tank in between updates, but there is much more at play than just the lighting.
In the earlier photos where the acans are puffy, I was feeding a mix of Cyclop-Eeze and frozen Mysis to nearly every polyp around 3 times a week. Even with nearly total weekly waterchanges, I couldn't keep up with excess nutrients. Caulerpa, GHA, and bubble algae went nuts and eventually I got tired of the manual removal every week that made a waterchange take over an hour. As the photos show, the LPS showed their appreciation by puffing up. I should have taken a pre-waterchange photo to show my conundrum.
Finally my hatred of nuissance algae won out and I installed a GFO reactor, turned the back chamber into a refugium, and switched salts to HW MarineMix Reefer. I also cut coral feedings to once a week maximum, usually every other week, using MUCH less food. This is when the puffiness went down a lot.
After running like this for about a year, I switched the MH to LED.
I didn't expect 4 RB, 2 Violet, and 1 CW at 700mah to be much brighter than a 70W MH bulb with 4 RB LEDs...but the corals definitely noticed. For the first 2-3 months the Acans got much lighter colored and were nearly on the verge of bleaching but this was quickly followed by an intensification of coloration that has lasted since. Now that algae won't grow in the refugium, I am slowly feeding more and more often to make the LPS happier.
So would I switch back? After the pigment intensification the corals showed from the LEDs, no way. Photos don't really capture it, but the corals were dull under MH for lack of a better word. Now they have that sheen to their colors like the reflective tape on street signs. If I wanted more puffiness, I could add a dimmer to the LEDs but it still wouldn't be like the puffiness from tons of feeding.