I am not as well versed in NO, but i"ll give this one a shot.
1) Why would you have more O2 in your blood? In NO2 itself there is no "oxygen" and free radicals are not just oxygen. They are oxygen with (I believe) one unpaired electron and therefore are very reactive because of that electron.
2) Antioxidants are always good, I wouldn't take anymore than you normally take though, I don't think more=better.
3) I don't think so. Oxygen radicals are created during cellular processes, and the body has its own mechanism for dealing with it. I don't think NO2 would increaes that at all. Free radicals always cause cellular damage, but that isn't a problem unless you are deficient with certain vitamins that act as antioxidants.
Kabookie, I don't think you can ever 'whipe the slate clean.' With increased exercise you have more free raidcals (as a by product of cellular "work"), so naturally as an athlete you will have more. I don't think that a fast would help. IMUO (im my uneducated opinion) I would think that it would be worse by possibly robbing yourself of antioxidants. I also think that free radicals cause acute damage, and chronic damage from an elongated state of lot of acute damage is what causes the real problem. This means that you don't "build up" free radicals, so taking a month to cleanse doesn't make sense.
Also, if I am wrong and you do build up free radicals, I think that a fast from supps also wouldn't help because supplements don't cause them. You would be better off not working out or causes your body any stress and taking anti-oxidants. Not good for someone just turning pro. I say don't sweat it.
Oh, KK, good luck turning PRO. You better wear the shirt we were talking about.