Thoughts on brightness
Disclaimer: Forgive me if this is again redundant, but it's kind of hard to word this in a way to successfully search the site for answers.
My last question about warm/dark strings for my friend's bright violin got me thinking. Are warm and mellow strings what bright violins really need? I've noticed some neutral or brightish/neutral strings (in my experience, anyway) such as Tonicas, Dominants, Visions etc. can sound quite nice on many violins including bright ones. Will attempting to mellow a bright instrument ever truly work? Does it not mellow it as much as just hide some of that violin's voice? I can understand not using excessively bright strings, as that will only hide some of the violin's natural warmth, but a constant strive for warmth and mellowness seems like you're trying to make the violin into something it isn't.
Maybe you need to broaden your thinking. If the instrument is so bright its beyond too much, try cutting a new bridge thicker than what's on the instrument now.
You can also adjust the brightness of an instrument by slight movements of the soundpost. Further to the "left" from the treble-bridge foot will reduce the brightness. A mm or two further inward from the ft-hole will enhance the lower frequencies. In my experience this works for most instruments although some are more sensitive than others. For highly arched instruments the range over which a given soundpost can be moved is very small and a different soundpost may be needed (even several of them if you are experimenting). But the relatively flat "Strad" top allows for reasonable movement of the post.
Everyone perceives sound differently and has different preferences, so it really depends on what you want. Then, you could try a bunch of things to achieve what you want.
There's nothing wrong with trying to mellow a bright instrument or vice-versa. Its all just personal taste and how you are using the instrument. Keep in mind that bright usually also means that it projects better so if you need that projection, switching to a warmer string will make it harder, even if you enjoy the sound more right under your ear. There is no single right answer - everyone has to explore and find what works best for them.