Whcih marker
The eternal question. I know back players playing with Cockers, Shokers, Mags, Angels, Busheys...
As Gurney said, shoot whatever you like the feel of, with whatever you want to do (i.e if you need to lay down loadsa paint, then maybe a phantom isn't the best choice; but if you go for first ball acuracy to catch them maybe its just the one you want.
So if you like your shocker, get a nice set of barrels for it, and you are all set
Richard