Well, for a somewhat off-the-wall answer to your question....

My moulds now number eighty or more, and my top punches.... I'd be surprised if there are more than twenty in the shop.

I reckon I'm using mis-matched punches more often than not. In practice, I just select a punch that "approximates" the shape needed, without making rings or cuts on the bullet.

One useful stop-gap is a 1/4" bolt mounted head-down as a top punch. Remove any irregularities on the bolt-head with a file or stone, and it will work rather well. A small flat created on the bullet by the bolt-head won't do much harm, if any.