Well, as far as I know there is no way of determining the height level, except for taking the wheels off, and checking how much further you can wind the spring holder down or up. This is where the "key" that you have comes in handy. The lower the wind-down, the lower the car will sit.

As for the 'setting', this refers to the damper setting. IE: the softness of the ride. You are able to adjust the damper, using the nob on the top of the coilovers. Front ones are visible when you open your bonnet and look at the coilover fitting, and in the boot, move the covering, and adjust it there.

Hope that helps..