Power supply should be fine. Most mining software will let you monitor the gpu temps if they consistently push over 90*C they are getting too hot. Type of fan really doesn't matter as long as it is moving the hot air away from the cards.
If I over clock a little will it damage the psu?
How can I monitor how much the components are asking from the psu. I have a watt meter but that will only tell me how much the psu is using.