The output of the RKL ACL module is a bit weak and not really designed for LED Drivers. To be honest it may work fine but would not be surprised if it does not. I dont recommend controlling more than one or two drivers.
My understanding is that the ALC will only dim 2 drivers. Therefore, I was planning/dreading to eventually buy 2 ALC modules. Would it be possible to build a module capable of controlling 4 (or more) drivers via the RKL? if so, how hard would it be for someone who has minimal electronics experience to build, and what would you estimate the cost of parts for such a project?