The YouTube link is using Farjan's method. The dichlorofluorescein is an easier indicator to use that chromate or thiosulfate. The calculation remains the same: you use the titer of your silver nitrate to determine the amount of chloride you have. What is your current method, and what specific problems are you having with it? You want 94-98% purity, what are you getting, and what is it a problem? A problem with your NaCl source? Or a technician problem? Have you review this page from Borek:
's site highlighting common titration pitfalls? http://www.titrations.info/titration-errors
If you have high volume needs, you might want to look into purchasing an automated potentiometric titration system.