"I don't really know how to tie a fly until I've tied a hundred dozen of them". John Gierach
First, the toughest trout, the ones that are burned into my memory, have never been Swift or Farmington River trout but are freestone river trout such as two that I took in the Millers and the Squanacook over a span of 20 years. Why is that? That's because those two trout found a spot in the Millers that they felt safe in and never left those two spots for the entire season. Their chosen spots were fairly shallow drifts with overhanging brush which meant your casts had to be PERFECT. One bad cast, and there were many, and they would be down for the day, sometimes longer. I never really encountered that situation on tailwaters where the whole river is trout friendly. A Summer freestone has fewer friendly spots and you have to find out where they are.
A Squannacook brown took advantage of it's overhanging cover for over two months until a perfect cast of a size 16 sulphur (type) fooled that 16 inch brown.
I fished for a very reluctant brown on the Millers from early June until my October birthday. Its spot in the current was almost impossible to present a dry fly to. It was still hitting emergers even after a night time rain so I switched over to a size 16 partridge and orange SH, draped the leader over a boulder and finally hooked it. It was only 12 inches long but if every future trout is exactly like that one I would be fine. P.S.
In short, I've caught plenty of bigger trout but not better trout.
P.S.
There's a brown on the Ware River that has found the perfect hiding place and has tempted me for two years. Maybe this year.....
Ken