yes, i agree with vulperin
1. yes
2. yes, int affects attacks, int is only way to be a nuker (if you want to be one, very suggestive)
3. not so much with a 3 lvl gap, but maybe with a 5+ will be a lot more helpful, with a 3 lvl your not getting a lot of sp, but more than if you werent gap'ing. i would suggest a 5 or 6 lvl gap for that, wold be much easier
4. no, very hard (as i explained in #3)
and dont apologize, just review. search button is an amzing tool
