Sometimes the anchor fly is heavy for short line dredging of a fast running slot. However, this short piece in the Harford Examiner by Alain Barthelemy suggests, in shallower runs, a big but lighter fly is in order.

Stonefly by Greg Lowry of Boise, Idaho

Query both Greg Lowry (SwittersB) and Alain Barthelemy (net) re woven nymph techniques.