I've got a few Marshall effects pedals (e.g. the Vibratrem VT-1) and I love them, except for the terrible design of the knobs. They've got a shiny chrome, dome-shaped top with a small black mark which wears off after time, meaning it becomes impossible to read them especially in any dark room. I've searched in vain for replacement knobs with a different design. My understanding is that the shaft is a different size/shape to Boss pedals so Boss knobs wouldn't be compatible.
Is there a third-party knob out there which will fit my Marshall pedals and be easier to read?