See this picture (from HKJ review). On the upper right side is a place with 2-4 resistors. They are stacked. I have seen slightly different values on these drivers.. 5A driver usually have 4xR200 in that location I believe. Just remove one or two if you want less current. If you have a 3 amp version, add R200, or R100 depending on what current you want... I cant remember the exact values for the exact currents, but that is where the business happnes.. :)
About the some of the "concepts" in this thread. It seems like RMM have a zener modded FET 105C driver that can handle 3S cells and 3S emitters. That might be the solution to making fully programmable direct drive drivers for larger multi-emitter lights....