Hi, I have a few on nymphs while after trout on the River Towy a few years back, fished tight into steep banks on the other side I did get nobbled by a few sewin. The patterns I used were home made so sorry no names to these, one was a pink sparkle czech nymph with a red brown shellback, and the other a very basic pattern just front half peacock herl and rear half copper wire tied czech style tied quite large around size 8, these seem to sort out the larger trout as well...which was nice

cheers Glyn
I have also had a salmon on a very large flo lime green ptn tied on a L/S size 4 from the same water.