i have an idea.
Did you know which vintage nib has the same size and shape modern #6 nib as Bock,jowo,goulet etc...?
If you can not check know because you are not at home.
I hope i will get an answer after you come back home
Actually i know the size of bock nib here=http://www.sbrebrown...g-5-and-6-nibs/ but as you said it can have problem with shape of curve to fit the feed...
PS:i dont speak english very well ,hope you understand
Edited by Toshinden, 23 January 2018 - 16:56.