I'd say you need to devise a way to raise the table to the lamp.
It's very important to keep your light as close as you can to the canopy. This is because of the way light looses intensity as it spreads. At 2' away, you'll have 1/4 the intensity than you would at 1'. At 3', you'll have 1/16 the intensity than you would at 1'. See what I mean? It drops off very quickly (exponentially) as you get further away. This is called the inverse square law.
So, back to adjusting that thing.
One option I could see would be several sets of light hangers:
Your res should way about 120lbs loaded. These are rated at 12lbs ea, so you would need like 5-6 sets of these, or find a similar, higher rated set of 4. Mount to a board and the wall and use this "elevator" to raise and lower the system.
I've done similarly with the lid/plants in a rainforest system. It worked well, but a lot less weight.
Another option would be to use heavy duty adjustable shelving and only adjust during res changes.