After owning three pairs of really tidy 15” Golds (far nicer than the ones typically going through eBay) I’ve come to the conclusion that rudimentary pair matching is the price of owning what for me are maybe the finest speakers I’ve ever heard. My current pair are very good, one just has a couple db more above 8kKz, the mid is pretty well balanced (certainly the best of the three pairs I’ve owned). I’d pay ridiculous money for a truly perfect pair, but I accept they likely don’t exist! I just stick the slightly brighter one on my deafer side and won’t touch a preamp without a balance control. I’ll eventually get to working on my Decca Ribbon tweeters (as supertweeters) crossover as I’m pretty certain they’ll even the Tannoys out, but they are too obvious at present, so I need to rethink the crossover freq and slope. They are just sitting on the Tannoys unused at present.