I do all brazing myself.
I have built several recumbent bikes and customized a few frames.
The 3 * 9 is interesting. The 3 * 7 seem to work well on my girlfriend bike. I don't like the weight AND i know little about internal hub. I would not like to be stuck in one gear and not knowing what to do (principally on the road). I have been a bike mechanic for 10 years but we didn't have to work on one internal hub. Really few people ride them anymore in my area (ok far east in Quebec province). I am really open to internal hub but i would need to learn a lot of things on them. Right now, i prefer what i know.