Just curious - What is the minimum required open space between the limbs and the riser cup? Can the limb bolts be tightened all of the way down to a ZERO GAP or should I maintain a open space? If so how much of an opening is required. ALSO should I shoot for perfectly even spacing on both the top and bottom? Insight regarding this topic will be appreciated. I was thinking about using my spark plug feeler gauges in this opening to measure precise gap if that is required.