What are the shuirim in inches to satisfy most if not all the shitos (like the Chazon Ish) with regards to a talis kattan and if that is not possible, what would be the next level. Thank you.

Tha Lechatchila size of Tzitzit is one square cubit [Ama] in front and back not including the head opening. Bediavad the minimal size should be at least three quarters of an Ama. According to the Chazon Ish an Ama is 58cm [22.835 inch] and for Rav Chaim Nae 48cm [19.9 inch]. The minimal Tzitzit 3/4 of Ama according to Rav Chaim Nae is 36cm [14.17 inch] When you buy a Tzitzit in the shops you don't need to come with a measuring tape, there are numbers for the different sizes. For cotton: #9=Ama Chazon Ish; #8=Ama Rav Nae; #7=3/4 Ama Rav Nae. For wool: #6=#9 of cotton. #5=#8.