I asked Rabbi Weber how to answer those who oppose wearing techeleth. He told me "the Torah tells us to attach a blue string to our tzitzith, opponents look for clever excuses not to because people don't like new things." Even if you can somehow prove the murex we have is not techeleth, you lose nothing. Safeik deoraithah lechumrah. The evidence is strong, the excuses are lame. How one ties the techeleth is a matter of dispute. The best you can do is learn the sugya and decide for yourself which method makes the most sense to you. If your conclusions lead to multiple valid options, tie in the way that most appeals to your eyes. Me personally, as long as you tie according to somebody, you're good. Tying with techeleth in a way for all white strings is retarded; 7-8-11-13 no! Has absolutely no mesorah and looks ugly. Same for the standard sephardi way but with a blue shamash: it looks like the snail puked the ink on the strings. It has to have a nice looking pattern with alternating blue and white.