Mcflyangler, I am going to back up a few posts here and talk about the size of the flies being so small. I have never been to that river, but have read so many articles and posts from other forums on it, and they say the same as you, that small flies from 24 to 28 is the ticket. The Dream Stream is the same way, and draws many fishermen as well.
I am starting to wonder, and I am going off of what was said about the 100 fishermen, ( whether there is a 100 in eyesight or not doesn't matter ) because the Dream Stream can have many fishermen on it as well, and it too holds big fish, hence the name Dream Stream.
I am wondering if the more pressured the fish are, and big fish are not dumb, the more they are attracted to smaller flies. I am assuming you were fishing pools, or areas of the river that have slower current? The Dream Stream is like that, so I am believing that a larger fly gives themselves away allowing the fish time to inspect them. Maybe fish have bad eyesight and have a hard time inspecting a size 25 fly while we as humans have to just watch the end of the fly line and hope for a twitch? LOL.
On the rivers and streams I fish, I generally use sizes 14 to 18, but I fish fast pocket water and riffles, so a larger fly works. I also fish waters that are not so populated, like the creeks above Boulder in the Indian Peaks Wilderness Area, not too many people fish the creeks because they all head for the lakes, so I have had the creeks and streams to myself all day and not another person insight. Pure heaven!!!
But if what I said above seems to be the picture on that river, it makes sense to me that it will take smaller flies. And for your tippet breaking, is your rod a fast action rod? To try and thread 4X tippet onto the eye of a size 26 fly eye is not going to happen, so I can see why you are using 6X. But as mentioned from another member, it is difficult to keep large fish on with such small flies, so my advice is to use a little softer rod, and when hooked into the fish, don't point the rod tip at the 12:00 position. But you probably already know that.
If I ever get to that area, I am going to have to try that river out. It sounds really challenging.