Most any of the piano supply houses that do custom hammer boring
(Schaff, APSCO and others) will bore the hammers to your specs, or
they can supply "stock" bored hammers that come in various boring
distance increments.  These will fit most North American pianos built
in the first thirty years of the century.

The "proper" dip (I assume you are referring to the hammer profile
rake angle, if any) is up to you to identify, and inform the supplier.
Or, you can send the supplier sample hammers from the piano.  I have
not had any problems with the mentioned suppliers accurately reproducing
the rake angle from samples, where one existed originally.

Doug Rhodes