other than you return your fish there, info is hard to come by, it seems to be MI5 stuff, I met one guy who had fished it and caught cracking trout wouldn't tell what fly he was using,but it was evening fishing, I hope you get the info, easker1
Fished there a lot and would suggest you try a "potty palmer" on your top dropper. See the Orkney Trout fishing website under Fishing/ North Isles. The inventor Davy Pottinger is a personal friend of mine. I've had fish over 6lbs on a size 10 black snatcher. Various muddlers will work as will shrimp patterns. Don't forget to try the North Loch- the fishing there is excellent too.
Tight lines. I hope you do well!