As an example of how sensitive handling is to fork rake, I once bought a used tall frame which was afflicted by the lousy geometry which too many mfgrs put into their large frames.
It would go into uncontrollable high-speed shimmy over 30mph.
After consulting Dave Moulton's articles about geometry, I made a bunch of measurements and ordered a custom-made fork.
The change from a fork with 45mm rake to one with 38mm rake cured the high-speed shimmy.