Hi Andy, super valid question. I'm very inexperienced. I took a brazing class last summer in Portland (UBI, great experience, highly recommended) and built one lugged frame. It is my commuter with 26" wheels, and the proportions and angles are much more normal!
Half the class did fillet brazing, so I learned the theory and watched the instructor demos, but didn't actually do any myself. Luckily, one of my classmates who did do fillet brazing is from the same city as me (Vancouver), so I can hit him up for advice.
In any case, I'll get some spare tubing and practice first. But it looks like I won't be running out to buy that lugset just yet.
Thanks again for all your advice and help,
James