Brace / string length for 1965 Bearcat

[brnwdrng]

I've recently purchased a vintage 1965 Bear Archery 41# Bearcat for my wife (haven't received it yet), which according to the ad measures 66" (not verified by me).  I need to determine the appropriate length for a B-50 string, which I've read by varying accounts should measure 3-5" less than the AMO length.

I've been reading about brace height for Bear bows of this era (not specifically the Bearcat), and understand how to tune, but accounts range from 7-9".

Given a string length range of 61-63", and a two inch range of possible correct brace heights, I'm wondering how to avoid having multiple strings made just to determine the right one.  Is it even possible to twist a (12 strand) Dacron string enough to reduce brace by up to 2"? Or, if I got a 63" string only to discover it's too long, can it be twisted down as much as two inches (seems implausible)?

I couldn't find Bear's specs for the bow online, which would save such experimentation. Anyone simply know the original specs?