I just read the
Wikipedia entry for Wingsuits, and it makes interesting reading.
A typical terminal velocity wearing one of these suits is around 60mph, and with a typical glide ratio of 2.5:1, you're going to be doing 150mph horizontally. However strong the wish to touch the side of the rock face would be, I'd suggest that at 150mph even a slight touch would probably break your fingers, and possibly send you into a likely fatal and uncontrollable spin for a very brief time before you collided with whatever you had just touched.
They also say that "The United States Parachute Association (USPA) recommends in the Skydivers Information Manual that any jumper flying a wingsuit for the first time have at least 200 jumps and be accompanied by an instructor, or 500 jumps experience to go without an instructor. ..." As others said upthread, they would need 300 freefall jumps to become qualified to learn how to use a wingsuit in this country, which I guess is comparable to the US. This does make a lot of sense, since I suspect there are a lot of ways which things can go wrong with a wingsuit, and probably little time to correct them, so you have to be really comfortable with freefall, and not likely to panic.
Even reading the Wikipedia entry, it's clear that jumping from a plane vs jumping from a stationary structure is quite different, and requires radically different approaches to the start. I guess if you get things wrong at the start, you've got very little time to sort yourself out before "splat".
The Wikipedia entry also
links to an article about a guy who is considering landing one of these
without using a parachute. Gods know how they are planning on making sure the vertical speed is survivable.
It looks fun, but I don't think I've got the dedication, nerve, enough money, or sheer care and determination to get to the point of trying this out.