Yomega Firestorm (Unresponsive Edition)

I've been playing with my Firestorm for a few months now, and it has gotten more responsive as I've played with it. I have switched to polyester strings (Expert strings from yoyoexpert.com) and it gets more and more responsive. Other than pressing down the response O-rings, or swapping them for silicone, what can I do?

I think that the stock string is cotton, prone to braking. The spare is polyester, which holds up a little better. In general, you will want to look for polyester strings when you are looking to buy replacements. We yoyoers tend to like "kitty" brand strings, but the generic stuff is fine enough for starting out. ps. to reduce the wobble and the "semi-responsiveness" make sure your "string tension" is neutral. To fix it easily, just take the yoyo off your hand and let the string hang down to relax (hold the yoyo in your hand, with the string dangling)

and as an additional note, adding a small amount of thick lube can make this responsive. Some people point to 3-in-1 machine oil or petroleum jelly as a good substitutes for thick yoyo lube.