I adjusted mine as it was the same as yours and wanted a brake light to show as soon as I squeezed the lever
I never thought of taking a tiny amount off the plunger
I milled a small indentation into the lever, der
It is only a very tiny amount you need to remove though
I'd use sandpaper and keep trying it till right, if you cut to much off, it's a new switch

__________________
you win some, lose some, crash some
K+N filter, snorkel removed, homemade kev mod (with his blessing), co raised,
Pipeworx cans, r1 led back light, under tray removed, small indicators, handguards, cnc short levers,