On techelet ratio, there seems to be a clear psak for different groups. This is just a summary of my halachic research and how the final positions trace back to the earliest source available, this is not an exhaustive list.
• Halacha l'maaseh for Ashkenazi
2:2 ratio based on version 1 of Bet Shammai, Rashi & Tosfos on Menachos 38a;Rosh on Menachot, Hilchot Tzitzit 6:1, Tur 11:1, Bet Yosef 13:1, Mordechai (brought in Bet Yosef), Bach 9:2, Taz 13 on Shulchan Aruch 11:12, Prisha 12:6 in the name of the rishon Menorat HaMaor, Shulchan Aruch HaRav 11:1, Mishnah Berurah 9:7, Aruch HaShulchan 9:2 and 11:2, and recommended and worn by R Schachter and R Belsky.
(Ashkenazim have a minority opinion of 1:3 based on version 2 of Bet Shammai, the Raavad based on Natronai Gaon, one of the opinions of the GRA. Discuss with your rabbi if you wish to follow this minority opinion)
• Halacha l'maaseh for Sephardic and Yemenite
1:7 ratio based on Rambam and Sephardic acharonim like the Ben Ish Chai, recommended and worn by R Mazuz.
• Halacha l'maaseh for Mekubal
A bit more complex psak as the Ramak paskened like Tosofos but the Arizal and majority of later kabbalistic sources paskened like the Rambam. Practically speaking, the opinion of the Arizal is followed by all mekubalim as the final authority on all matters.
• Halacha l'maaseh for Chassidim
Chassidim, specially Breslov and Chabad, follow the ruling of the Arizal as final. Nevertheless, some chassidim, based on the Baal HaTanya Shulchan Aruch Harav mentioned above, may wear 2:2 ratio.
A baal nephesh of Chassidic background may want to be yotze of both opinions (Tosofos /Ramak & Rambam/ Arizal) by wearing different ratios in the tallis katan and tallis gadol. In order to justify this approach, see Shulchan Aruch HaRav 25:27 regarding the similar issue of Kabbalah vs Nigle וִירֵא שָׁמַיִם יוֹצֵא אֶת כֻּלָּם, and Minhagei HaChida regarding different mutually exclusive tzitzit tying styles in the tallit katan and the gadol, and he writes: דברים מירא ה׳ וחושבי שמו, נהרא נהרא ופשטיה.
ודאי התורה אמרה שיש ליתן בכנף שני חוטים לבן ושני חוטים תכלת והלכה למשה מסיני שהתכלת אינו מעכב את הלבן והיה מספיק לנו בשני חוטים לבן אלא שאנו נותנים עוד שני חוטים זכר לתכלת
– Gershom Menachem Feb 01 '23 at 12:41