The hight from take off site to landing zone is about 300m; Take off is facing south. The slope is about 30degree (it looks like 45 degres).http://www.wingchina.com/en/flying%20the%20great%20wall%20of%20china.htm
This site is best for June to Oct.
Access
3 hours drive from Beijing, 120km. The Simatai Great Wall is a famour place to visit ,so nearl every local driver know how to go there.
ORIENTATIONS
WindNNEESESSWWNW
WEATHER
Basically S,SE,SW wind can fly, and the take off site is at the half height of the mountain, so you should check the real wind direction