2 words. Contest Balsa.
It is expensive, but worth the weight savings.
Please don't be discouraged by this advice, but a warbird is not going to get you in the air unless you have a fantastic pilot working with you at all times. Even then I wouldn't recommend it.
I would strongly recommend you train on a RCM Advanced Trainer or a Trainer 60. They are hard to find but worth it. A symmetrical wing is far easier to land than a flat bottom wing to both fly and land. Joe Bridi knew what he was doing when it came to these things and I agree with his design mentality.
If you need plans, let me know... I can direct you to them.
Brian