Not sure how to rig up a fork brace on UD forks. The spring is probably going to be noticeable, but other mods aren't really going to make much difference unless riding round at 10/10ths, which I try to reserve for closed courses.
My Nordie would tend to try to 'stand up' if laid well down in to a fast ripply bend and you had to fight the bars a bit to keep it on line. As Kano Nordi says hill climb tracks aren't like public roads, or even short circuit courses, and I don't think he's ever been to Hartland Quay
I did rate the 'Quadrant' upgraded rear shock I put on mine with ride height adjustment and damping tweak screw. That would be a better place to start with suspension enhancement. A lot of handling problems actually originate at the back end rather than the front.
"Do not adjust your mind, there is a fault in the reality"
1957 175 Sport