Andrea,
It's really hard to get that feel when you're stage II. You have my sympathy--I've been in the same spot you're in and then, even after I got the report that margins and nodes were clean there seemed to be disagreement among the doctors I had at the time abut whether I needed radiation. Its really stressful feeling like the decision is all on you!
Even with clear margins and nodes, from what I learned during that very intense time, there are other factors that may show up in the pathology of the tumor that indicate radiation would be the safest way to go. I can tell you what I was told those factors were in my case but I'm not an oncologist and the reading I've done suggests to me there may be others as well--and that different doctors may disagree on how serious some of them are.
Could I suggest that you might want a second opinion at that point? It's what I did and it made me more confortable with my final choice. Having the sense that there is not just one clear path and that you have some choice can be very stressful but the benefit is it also makes you very committed to whatever path you end up choosing. More so than if some doctor just told you you had to. At least this has been my experience.
When I was making the choice, the biggest question for me became this: if I get a recurrence, how will I feel about the choice I'm making now? I ended up concluding that I would have a hard time forgiving myself for not having radiation the first time if I got a recurrence. It was just something I needed to do for myself--to fight it as hard as I could the first time. But I'm still paying the consequences of that--including having mouth problems that may keep me from teaching in a classroom full-time--which is my passion. So there are sigbnificant costs as well. Whatever you decide, you will find support here.
Nelie