Just curious, but are you just getting started into rocketry? I am not dismounting your like for this set, but I hope it is serving you well. Most experienced rocketeers tend to dislike RTF starter sets mainly because there is no hands-on involved in getting the rocket built.
I agree that most RTF kits are good for getting someone to *try* rocketry, but for some people they never get beyond the RTF stuff or venture further into the hobby.
Best of luck with your Tidal Wave rocket. You should check out some Skill Level 2 or any rocket that requires some hand tools. There's just something special about taking a pile of parts and making it fly!
Your right, I think the Tidal Wave is a very nice rocket. I would replace the shock cord with something thicker (1/4" eleastic from Walmart works great for this). Easy to fly, great for those launches where I can not launch my H, I, or J powered rockets.
I wouldn't use a C6-7. I think a C6-5 would be a better choice.