Caught a load of them on the dry fly in a shallow mill pool in France last year - most of them on a didi little Klink (size 18 or 20 if I recall correctly) but tried a few other types and any sort of small parachute hackled fly seemed to work ok in late afternoon in August.
Water was very clear and I could see them in front of me positioned just to the side of the fast flows amongst the weed (in my avatar photo), placing the fly within a foot or so, to the front / side of them with really light leader and floating line was great fun!
Was viewed as a bit of an eccentric
Ros Boeuf by the few locals about where we stayed but they had to appreciate the success of the method in 6 - 18 inch deep water, where theire normal methods couldn't reach.