Andy and unterhausen, thanks for both of your insights. I followed this board for a while in the lead up to beginning my build, and I came across your posts often while doing so. It's a real pleasure, and reassurance, to hear from you guys.
For what it's worth Andy, you were spot on in terms of the speed things happened with the silver filler. Owing to advice I got on this board, I purchased 0.058" tubes from Spruce, cut them up, and practiced on them as "lugs". All in all, it was great advice and practice. However, the much thinner real lugs came to heat in what felt like no time and the silver was really moving. I can see how a slower moving filler would be better for the first timer. In the end, I clamped down the largest gap during a rebraze and flowed some filler through it. Now it looks alright, althoug the lug is about two degrees off. Hopefully I can cold set it to place. My miter and fit pre-braze were good, so I have a feeling that the lift was caused by heat.
I hadn't really thought about clean up, unterhausen. I was just hoping for a good first braze. But you're definitely right, the globs are going to be a pain. Unfortunately I don't have the resources to cut it up and try this one again right away, so I'm going to have to go on the hope that my flow was as good here as it was on my practice brazes. I guess I'll just have to hope for a soft landing if the connection snaps once this thing is done.