With your Marvel S, I don't see a need for the Covert Revolt in your bag. You could probably also do without the Tag and not have a huge gap between the Octane and Ascent. The Sigma Sting may be a bit of overlap as well, but mine is my favorite ball, so I would never be without it.
That's still a lot of balls to carry. You need one of those 8 ball rollers like Kip.
I agree about the Tag. It is my least favorite ball that I have used the least. With how polished my Octane is , I use it for a lighter oil step down from my Sting.
I thought the Venom Shock might replace the Sting, but they are just different and the Sting may be that special.
I just got a majority of these so maybe I will fall in love with one over the other. Haven't thrown the Talon. The Covert does exactly what I wanted. So does the Venom. Don't care for the Primal Rage yet even though I went + 245 for 6 at Pacific. Sting is awesome, Octane love/ hate. Haven't tried it much with the new 1000 surface then polish. Tag-- boo, but have used it with success. Ascent, so clean, just floats to where I want it to go. Rebel Tank- Not sure yet., Arctic Sniper, I like it.