While the electronic copy of the GCR is not the official one, I pulled the rules quote from the 2009 GCR on the SCCA website. Is there a different version available that doesn't have the wording I quoted from the 2009GCR.pdf rulebook?

One tube sounds pretty clear to me, even clearer considering the any number of tubes doesn't extend to the allowed firewall, err, dash panel pickup. How can it be interpreted to mean two tubes going to the dash panel, even if they do only touch the dash panel at one point?