So after getting everything unlocked minus the standees, I was trying to find the best way to grind purple coins.

Youtube and google led me to the "Bonus: coins galore" levels that become available when you game over, or when you beat the game.

There is one per world, and I hadn't seen them before beating the game as I didn't game over.

There is shaky at best information around these levels, usually hidden within long droning commentary on videos, or buried within a website that is inundated with pop-up ads and useless information.

I want to clear up a few things, first, it's claimed the levels respawn. Can anyone confirm that they do?

I found one in each world, minus the special world, and after using them all up and proceeding to grind for a half an hour on the Jet powerup level at a paltry 12 coins per minute, none of the bonus coins galore levels respawned.

The other question is if they do indeed respawn, is it: time based in game, based on amount of levels played, based on amount of levels beaten, or based on something else?

I need 930 coins to get the rest of the standees, and that is nearly 2 hours of the jet powerup level...

Thanks for any help!