Ditto on focused task boxes. Small-medium plastic ones work fine.
One for carb, which includes carb-specific tools
One for ignition & spark plugs & timing light & minor electrical stuff
One for chassis - snubbers, leaf clamps & such
Bigger top box will live in the Dually during race season, with a few additions out of my bottom box.
Any serious problems other than unanticipated breakage (thankfully rare for me) told me I wasn't on top of my stuff.
My philosophy, as taught to me: show up ready, organized & clean, or don't go.