I would look at a lower power than 30x. I shoot out to a grand pretty regular and I rarely go above 15-17x. In fact most of the time out to 800ish I am about 11 power.
Buy as much scope as you can afford. You will never kick yourself for buying good quality the first time. No matter how you choose to use your dope, a good quality scope is a must have. Definitely dial the elevation and hold the wind in the reticle. Holdovers at distance are difficult.
Read this article for some good some great info:
http://demigodllc.com/articles/intro...-rifle-scopes/