For decades, all commercial tracks (and a ton of club tracks) used a lane striping tool to paint the lane colour stripes, and it works equally well to paint inside and outside track boundaries. A little white emulsion paint and you can "roll on" lane marking/track limits in minutes.
Here is a pic of the tool, in this case used to apply lane colours to a BSCRA track......it has an adjustable guide, to maintain a consistent distance from the slot, or, track edge.
Not the best pic. to show, but, here is a pic. of my track with "painted" track boundaries painted with this tool......the "stripes will not peel up, will not be affected by cars crossing them, and if you use the same type paint as your track surface, the grip will be the same,.......very inexpensive, very durable, and very quick !!
Google "slot track lane striper", or, contact ABSlotsport.
Cheers
Chris Walker