Andrew F Ulrich wrote:Would it help at all to maybe lay some thin, flat pieces of metal along the flat of the strong of the blade in addition to weighting the handle and/or pommel?
Of course it is difficult to say without knowing how their waster is balanced in the first place...
However the key problem with the wasters that I have seen and measured is that their mass is not concentrated enough, not in the right place. For example, the basic idea to turn my longsword waster into something balanced like Albion's Brescia Spadona would be to add a big concentrated lump of mass at the cross (something weighing more than the whole waster, actually). This is impractical... Adding a bar might be easier but it will also be less efficient than a point mass, so it will have to be heavier to get the same effect, and it will probably interfer with your grip.
Adding two masses, one on the pommel and one on the blade, will be even less efficient and you'll end up with a very heavy sword. The structure will be less strong because you'll have all these added masses putting additional stress on the waster's core. So overall I wouldn't hope too much in an easy modification getting the waster to "sword balance", while keeping it solid.
I do think it would be possible to design a waster that is not accurately balanced like a sword, but still reproduces enough of it that it does not affect your learning too much. I'm just beginning to think about it though, so I wouldn't expect too much if I were you
As to the importance of having training weapons as close to the originals as possible, good points have already been made. I would add that it is especially important when there is no living tradition, because we are constantly trying to see what works and what does not with a real sword, refining the technical interpretation along the way. If your training tool is not authentic, the conclusions from the test are more or less biased.
When you have a tradition teaching you the correct gestures from the start, at least you won't be modifying them to fit your training tool better. I think that's why many traditional arts have a lesser focus on the authenticity of the properties of their training implements. Having the correct tool will just bring a superior level of comfort and intuitiveness...