Mine are on the inside using standard weights. Tires seem to be balanced correctly as I have not vibration at speed.
Without being hands-on within the specific instance, it is not reasonable for one to imply any specific fault or known results from any technique applied by others. But, if I am allowed to present a thought: it would seem unlikely, but not unheard of, that a weight value applied at a singular location even if clocked correct within the plane of rotation, positioned off center or as described at one end of the rotational mass in its' length, would be the correct solution except if the rotating mass produced a singular couple imbalance which when corrected, also solved an also present force imbalance sum, verses creating one.
Again, I would think that if one chooses balance something of the shape presented by a tire & wheel assembly with the correction as indicated above, then I would have to believe that one is only concerned with the force imbalance effect, and only if by luck, addressing the couple solution, if not inducing or compounding such. And this seems the inverse of the previous, but it attempts to indicate the difficulty in addressing what may be more than one imbalance value acting upon the rotating mass.
Think of it as, the "Force" balancing solution as a two dimensional observation, and the addition of "Couple" balancing within the solution as making it a three dimensional observation.
But, sometimes, just one, itty bitty correction is all that is required; I just wouldn't count on it!
BTW. if tape is required, the Gorilla Tape brand is generally tougher with superior adhesion vs. regular universal Duck Tape; just my experience anyway.
Scott.