....so let me try again.
Bicycle "trail" is the most important part of a bicycle's geometry for determining how the bicycle will handle. Trail is the bike's caster force that keeps it going straight. Because of a fortuitous combination of factors in bike design, as a rider leans in a particular direction, the bike's trail will tend to turn in that direction, putting the bike back under the rider and keep him upright.To imagine a bike's trail, draw a vertical line through the center of the front axle. It will hit the ground at the contact patch of the front wheel.Draw another line through the head tube. It will (it better!) contact the ground some distance in front of the vertical line. The distance between the 2 is the bike's trail.Bikes (like commuter bikes) that need to be very stable will have more trail. Racing bikes have less. How much trail is correct for a particular category of bike has been the subject of arguments since trail was incorporated into bikes over 100 years ago. When I was designing racing bikes, I liked the feel given by roughly 5.5 centimeters of trail. There are respected racing bike builders whose bikes have trail in the mid-4-centimeter range. It's really a judgement call. Here is a very good discussion of bike trail.
http://www.bikeraceinfo.com/tech/trail.html
So just to be clear, in case it is not already, increasing trail would be
a step in the right direction, if that is indeed the issue here. The simplest
way to do that is to decrease (shorten) the rake. You can also change it
a smidge by wheel and tire diameters, but not very much.
I still would look very carefully at what's going on in the headset and
the seating of the crown race........otherwise, I really got nothin' else.
Maybe like you said you just need to get accustomed to the new and
improved handling.