About Minyan Hachutim this is a machlokes rishonim between rambam, Raavad, and Rashi (and many other rishonim who go like Rashi)
The Rambam ( Hilchos Tzitzis 1:6) says one of eight should be made from Techeiles ( half a string).
The Raavad (ibid.) argues and says one full string should be blue meaning two out of eight.
Most of the Rishonim however say that half of the strings are techeiles.
Most of the people who wear today follow the Raavad’s opinion being that the gra was maachria like him. However I believe Rav Belsky, who should be zoche to a full recovery and Raav Shachter are noheg to wear 4 out of eight techeiles.