Probably x3 as much if the cheaper BASF cured style like on Tijmens and probably x10 if sintered. But I havent looked into it yet.
On top of that is the extra money for having it silver brazed rather than fillet brazed
I will sketch it up with some beans and see what Maj says
Out of interest, how much extra would magic bean dropouts run too?
(Forum whip round, this bike deserves/demands magic beans).