If performance is a concern, listen to the old guys that routinely competed in altitude. They wanted the least friction in addition to the least amount of tip-off. Most migrated graduated to towers, rails, and piston launchers (do they still allow that in any events?), but I bet they have a good grasp on lugs and rods too.

If performance isn't a concern, look at the rocket and see what makes it look good. A single longer one near the CG works. Big Bertha kits have been made like that for decades. A single long one near the aft end works. A shorter one at the aft end and another near the CG works, like with the old Cobra 1500 and Mean Machine. A shorter one near each end works if it's not a long rocket. The Cherokee-D was designed and built that way for years. In short, it won't matter a whole lot unless you just stick one short lug on the rocket.

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