Okay, yeah, I understand the experiment. We had a little miscommunication; I thought you meant that you were trying to find the maximum light output you could get from this led setup, but you were stating the purpose of the bacteria experiment.
I also understand that the electronics stuff is basically just a side-show for you; it's likely not your core business/competence. Nothing wrong with that. Would it be permissible and possible in your situation to team up with someone who could handle the electronics part for you? It would save you a lot of time and for someone with some experience with electronics, it would probably be something like a 1-day job to make an experimental setup for you.