If using stock points, cut the advancer springs ca 1/2 wound will make idle more stable.
Cut off the loop that fasten it on the tower.
Bend up a new loop with a plier or 2.
I had to do that on both my CB750 when using points to get ignition correct.
One bike had too sloppy springs so it advanced ignition way too early.
The other when plate could not retard enough for ignition to line up. Just 1mm off.
Both have Dyna-S now.
Still with cut springs to get ignition ok from idle and up.