I love Brittanies, too. My current one (Jackson) is now 15 1/2 years old. He is our third. He still gets around fairly well for his age, but gets up in the middle of the night even more often than I do. 😉
I can't say that I have a favorite fly. I suppose it depends on where I am fishing, and saddly I haven't been able to fish for trout in a long time. For dry flies, I suppose my most used was probably Elk Hair Caddis because most of my fishing was in freestone streams. For sub surface? Probably woolly buggers or something similar. For nymphs, I'd have to say it is one that I tie that is similar to a hairs ear with bead chain eyes. But I often use a different fur.
For me, recipes are just suggestions whether I am tying flies or making soup. BTW, I am much better at making soup.