A perfect truss tube design would taper at each each, with the fattest part in the middle. Several schemes such as filling the tubes with expansive epoxy and pre-stressing them with wire have been dreamt up to strengthen their resistance to buckling. Since we are aiming for the simplest, most minimalist design, these interesting ideas don't fit our scheme. The key is to make sure that the frequency of the vibration is not a resonant frequency of the overall telescope. And now a word about vibration, amplitude, frequency, and dampening.
Vibration is the to and fro motion of an object in the eyepiece.
Amplitude is the amount of motion, a convenient unit of measure is arc minutes, or even 'Jupiter' diameters. Frequency is the speed of the vibration, and dampening is the time it takes for the vibration to die out. The goal to aim for is an amplitude of less than a Jupiter diameter under 1 second dampening time. Large amplitude is disconcerting if your scope is sensitive to the wind. A higher frequency is preferred as 'the pants will shake the ants out quicker'.