If you want to stay within EBI, make sure a Track Paradox is at the upper end of your arsenal. This ball is the first EBI ball in a while that I've picked up (throw a mixed Storm/Roto/Motiv arsenal) and it's one of the heavy oil balls that actually doesn't seem to die in back. I just picked one up and will drill it within the next week. From what I've seen so far, it is one of the best balls any of the EBI brands has come out with in a long time, probably going back to the original Ebonite Mission.
From there, I would also want to fill a spot between the GB2 Gold and the Paradox. I'd lean you towards the Track Tour SiC. It's a good solid cover ball that will handle some heavier volume than the GB2 Gold but won't handle as much as the Paradox at the upper end. This would be a good option for you on fresh patterns where you're not in the soup but need something with a little more muscle before the pattern opens up.
The GB2 Gold is a good choice for medium patterns. To complement this, I would pick up the Game Breaker 2 Solid. This is good on true fresh medium patterns and would likely be your benchmark ball. Most times, you can start with this and then go to the GB2 Gold when the back opens up. In either case, you have a complete line for medium volumes and a good one at that.
I agree with the Cyclone for light volume. You have a lot of ball for that price point and is a great buy. You have the proven GB 10.7 cover which has been used on high end balls such as The One in the past and a proven core. Definitely one of the best options.
Finally, with any travel league or tournaments, make sure you have a plastic spare ball. One option I would consider here is the Track Spare+. It has a plastic cover, but you get the benefit of the I-Core used in Track's high performance line such as the Paradox. If you run into a situation where the lanes are a complete desert and the Cyclone is overreacting, you could use the Spare+ to possibly to bail you out if needed. Basically 2 balls in 1 at that price and it could be the difference sometimes between a win and a loss.
Overall, this is what your arsenal would look like:
Heavy: Track Paradox (hybrid)
Medium-Heavy: Track Tour SiC (solid)
Medium: Ebonite Game Breaker 2 Gold (pearl)
: Ebonite Game Breaker 2 (solid)
Light: Ebonite Cyclone (pearl)
Spare: Track Spare+ (plastic)
I think this will give you a good balance between solid, pearl, hybrid and even plastic covers to cover a wide range for you. Good luck with your decision.