my LWS insisted that safety-silv would work for bronze flux because they didn't even have the old borax powder standby. I consider this a favor because I know exactly how much expertise they have -- if it's not a gas fitting, they have zero expertise.

Henry James or Cycle Design are your best bet for flux and filler. See the Supplier thread

I never really got used to the Cycle Design stainless flux, I keep intending to try it again. When I'm a little uncertain about some silver brazing task, I use the black Safety-Silv flux. If you burn that stuff, hang up your torch until you can get to one of Doug Fattic's classes. If you're doing it right, the white Safety Silv will stay active for an incredibly long time too, but the black stuff is indestructible.