For a lot of fly tiers (or a lot of fly tiers like me, anyway), there’s always a bit of guess work when it comes to measuring materials before they are tied to the hook. Often, for me, it’s a “Well, I guess that looks about right” sort of endeavor.
As he’s been known to do, Tim Flagler has simplified the task with some fairly simple advice involving, of all things, hook length and your very own thumbnail. It’s a simple process that will make your flies more appealing and give them the appropriate profile when it comes time to fish them.
— Chris Hunt