I love acoustic guitar as well!! Especially the song: Big Love, played by Lindsey Buckingham of Fleetwood Mac, AWESOME guitar playing!!!
As to tweeters: I find metal tweeters too bright for me. I prefer: my B&W 805 diamond tweeters, as well as: silk dome, and ribbon tweeters. One type of speaker I’m REALLY intrigued by are: single driver, full frequency speakers. They are rare, haven’t seen any to audition anywhere yet. But I bet THEY are not bright or fatiguing to listen to. I’d REALLY like to demo a pair of them! I cannot afford them either! But I’d love to see how they sound!!
Hope I helped a little bit. I dislike “bright” sounding speakers and headphones, for that matter. I may be wrong, (tell me if I am), but I wonder if a really high-end pair of headphones beats a really nice pair of speakers?? I mothballed a pair of Klipch headphones I bought because they were WAY too bright! Gave me a headache! And I lost the receipt to take them back😢. Oh well. I really like my B&W headphones as well. Only issue I’ve had with them is the input cord is so thin, too thin, ones failed already, VERY delicate cord. But they sound so warm, and so comfortable! A touch lacking in bass response. Lambskin leather on the replaceable ear pads and the head cushion. Nice!