Managed to get there myself yesterday and the conditions were just as you predicted, although it was difficult early on due to the mist coming off the water. Conditions in the afternoon were beautiful and only about 4 fishing
Unfortunately I'm not in the same class as you guys when it comes to stalking and I didn't manage to find any of the doubles. Though I did see one early on in the top lake, but lost sight of him as he headed up towards the top end where you can't get to.......never managed to get a cast at him
That said, I finished with 4 all around the 6 - 7 lb mark and they all went like steam trains, not seen my backing that often for a long time

.
But the best part of the day was in the afternoon when I got my 6' 6" #2 wt out and went for a play on the feeder. The Grayling were feeding really well and I ended up taking a total of seven, with 4 over 1lb, including this lovely 2lb fish (sorry about quality, only had the phone camera).
All in all, a glorious day. Not fished there for over 2 years, but I will be back a lot sooner, I had forgotten what a lovely place it is
Cheers,
--
Bill.