The open spacer will effect the intakes dual plane design. But it may effect for the better depending on the setup. I would give the open 1" spacer a try and if that does not provide good low end power move to a four hole spacer for added punch down low.
It wont hurt anything and you can use the same type so you dont have to change the linkage if you want to swap the spacer. For the four hole type later on. A lot of people run open spacers on dual plane intakes as it will amke you intake seem bigger to the engine than it is.
hope this helps.