It shouldn't matter if you want to use 1 or 2 catch cans. The OEM hoes(s) are connected to the same vacuum source and the CCVs are sharing the same crankcase area. It would be interesting to note if 1 side passes more oil then the other with 2 cans. I think it is hit or miss as to if the valves close at all. There's 2 CCVs (springs) and the diaphragms have to counter the crankcase pressure "your" engine produces. That's also assuming "your" engine maintains the correct vacuum which is regulated by the valvetronics and throttle valve.