You've come to the right place, for sure. Many of us here use this type of gear for a living.

So let me see if I understand what you've got. 2 pairs of Valencias, one 8 ohm, the other 16 ohm, yeah? And you want to run all 4 (both pairs) at the same time, right?

IF that is the case, you will have some trouble with the 8/16 ohm thing. The 8 ohm pair run louder when driven with the same signal. I think that minimum you'd want 1 active crossover and 3 stereo amps. You can use the L-pad to bring the 8 ohm horns down a bit, they could be driven off the same amp as the 16 ohm horns.