The covert and vengeance are both great. You have a sigma sting which I think will be too close to vengeance. That's why I said covert which will handle more oil and it a bit smoother. The venom shock is stronger than advertised and is very very versatile. It a great ball. I want things that read the lane well and don't overreact on flat patterns.

On a flat pattern you will see more difference than on a ths. But as I said for me, I'm more successful with smoother equipment on flat patterns. You only bowl nationals once a year also.  that's just my take.   Don't over think it.

The stampeded would be more than enough ball if you go that way. If not the covert revolt would be a great compliment to the sting. I'm not familiar with your aura to be honest whether to know or not that one of the above balls would be similar.

Thanks you so much for all your help and your fast responses. I'm so excited about the Nationals, but at the same time I'm trying to not over think too much. I just want to have the right equipment and have lots of fun out there (and obviously try to make some nice scores) I'll think about the Revolt and the Stampede, but now I know that I don't really need a strong ball like a Guru, Jackal, etc for the Nationals. Thanks again and I hope that someday I would be able to help someone the same way you helped me!