We use zig-zag vortex tape on sailplanes to control the boundary layer. It definitely DOES NOT keep the flow laminar; in fact the purpose of the tape is to trip the boundary layer to turbulent flow to keep it attached. If you have areas of laminar flow where the boundary layer is detaching from the surface, the tape MAY reduce drag, but I personally do not think that the laminar portion of the boundary layer progresses far enough aft in an RV for the tape to do any good.
As a point of reference, my Discus has laminar flow over about 80% of the wing chord. The lower surface of the wing gets a seperation bubble at about 75%, so there is a strip of turbulator tape at the 75% chord line. This reduces the overall drag by a small but measurable amount by eliminating the seperation bubble, even though the turbulent boundary layer has more drag than the laminar boundary layer. Tape on the upper surface of the wing only increases drag. In contrast, you would be very lucky to get laminar flow to 30% chord on an RV wing. The turbulator tape would probably do absolutely nothing if you put it in a section of the boundary layer which is already turbulent.
Pat