Jones' point shouldn't be taken too lightly-
It's not so much the rake and trail figure that you measure when it's sitting still... it's the dynamics that CHANGE when you're riding.
IF you ever happen to have a front-end oscillation start, lean forward... get more weight on the front wheel... the oscillation will usually settle out... but downforce from wind on a fairing, or many other things... will have a substantial impact on handling.
Having spring problems on the front end... particularly... one fork tube that has a weak spring, or having just enough malignment in the tubes so that one slider binds at some point... or having improper damping oil or levels in one or both... will cause stability problems, as will a sloppy swingarm bushing...
And the most overlooked, is well-worn tires. If either of your tires have worn to exhibit a flat tread profile rather than rounded, it will get really touchy, particularly in curves.
When braking, having assymetrical load on the fork sliders will cause both steering stability and wear problems. Why? Because brake caliper force is twisting on ONE slider, but not the other. This is one of my greatest pet-peeves of 'integrated' braking... two front calipers that are NOT working together. My '79 CX500D had adequate fork tubes until I fitted the Pacifico fairing. it got a whole lot more stable at highway speeds, but more substantial springs and damping was clearly needed. I replaced the CX triple-trees and forks with GL-1000 units. I snipped off about 4" of the GL spring, and installed a sliding puck and 6" of CX500D spring, so that the spring rate at rebound would be a good match for the lighter bike. I ran 7wt fork oil, and of course, fitted it with a CB900 front master cyl and a second CX500 caliper, and the end result was a WHOLE lot better than the original setup in just about every way.
That being said, I'm not certain what front end parts combinations would improve a GL-series, but I'm certain there's room for it somewhere.