National FAQ: What does "gaps must have a horizontal span of at least 5.0cm" mean. Does this mean the track (vehicle leaves and vehicle land) has to be on the same level? Or launching track can be higher and landing track can be lower? (section: 3 / paragraph: i / sub-paragraph: / line: 3)
A: No, the tracks do not have to be on the same level. The "launching" track may be higher than the "landing" track. Measurement is the horizontal change, not the vertical/angular distance, from the end of the "launching" track to the start of the "landing" track.
National FAQ: Can the finish line be set on a track affixed to a board that might be adjusted or does it have to be on a piece of track that is unmovable? (section: 3 / paragraph: f / sub-paragraph: / line: 2)
A: Yes, the finish line can be on a board that is adjustable with respect to the rest of the device.
National FAQ: When it says, "a vehicle (i.e. a ball or sphere)", can we bring an actual vehicle such as a toy car, or do we have to only bring a ball or sphere? (section: 2 / paragraph: a / sub-paragraph: / line: 1)
A: No, only a ball or spherical object is allowed.
National FAQ: Can commercial roller coaster track be used? In other words, can we purchase and use marble track from a kit? (section: 3 / paragraph: b / sub-paragraph: / line: 1)
A: Nothing in the rules specifically prohibits use of parts from a commercial kit. However, in the spirit of SO, the overall design should be yours, not a simple kit assembly. Whether your design is sufficiently different from a commercial kit will ultimately be the judgment of the event supervisor during impound.