Hammer striking line

[Frank Weston]

Dear List,

I am in the process of rebuilding a 1912 Knabe model B grand.  As this
piano has had at least two hammer set replacements, and because many of
the hammers on the last set were broken or missing, the determination of
the factory ordained hammer striking line is impossible.  

I have considered hanging a few trial hammers at 1/7 of the speaking
length, and sliding the action in and out until I get the best sound,
and then setting the striking line from that reference.  Is there a
better or more efficient way to proceed?

P.S. To complicate matters further, this particular piano has very
different action geometry from other Knabe B's which I have rebuilt. 
The hammer shanks (to fit in the treble) must be about 1/8 to 3/16 inch
shorter than other Knabes and comparable sized grands of other makes.

Frank Weston