As a former Aberdeenshire Dee ghillie, I would still advocate the bigger flies for spring fishing especially in higher waters - however, treble hooks are now discouraged if not banned on many waters. I used to use Loop doubles, or simply a big short-shanked single instead on tubes and waddingtons, and often reverted to really big singles dressed with bucktail. They seem to penetrate the water and sink well. As regards summer fishing one of my biggest problems was to convince fishers from south of the border that a salmon fly could possibly be less than a size 6 or 8!
It was always difficult to get them to use minute flies - the equivalent of a size 16 trout double with a wisp of hair as a wing a la Stoat Tail style was enough, and a lot of fish will take tiny tubes on plastic - even electric cable insulation cut to around one eighth of an inch, with two quarter to half inch long wings on opposing sides, did brilliantly well. This is not to say that standard sizes and patterns from six to twelve will not do equally well on their day, but please do experiment in low water conditions with six pound leader and single small flies. Another tip in warm conditions is to cover the pools with a fly tied on with a ‘riffling hitch’ to create a wake - it often stirs up apparently uninterested fish, and once you have got them moving they will often respond to a small fly fished as normal. Another tip for low warm conditions, and cold as well, is to strip a Sunray Shadow fast through the pools - moves a lot of fish and even hooks some!
