You don't need the full x16 lane. x1 is all that is used anyway, however, I don't know how the driver will treat 3 devices per lane... you might just have to get it and see what happens.
I should also say that you will most likely see longer than average loading times for wordlists since you will be tripling the work over a x1 lane.
I should also say that you will most likely see longer than average loading times for wordlists since you will be tripling the work over a x1 lane.