

If you mean fly weight as in getting flies down or choosing the right fly-fishing setup, the strongest matches are the weighted fly and line options.
Switch to a heavier fly or added wire when your fly is not reaching fish fast enough. Switch to a lighter pattern like Mitchell's Itchy & Scratchy (Stealth) - Fulling Mill when fish are shallow, spooky, or feeding in skinny water. If you meant rod line weight rather than fly weight, tell me your rod size and target species.
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