dock dimensions

Is there any way to determine the dimensions of the dock for LWM? I 
need to be able to open an interface where the bottom of the window 
does not get stuck behind the dock. It is nice that :best-height 
:screen-height accounts for the dock, but if put a value for :best-y it 
is ignored and the window is the full height of the screen (and in 
LispWorks the top of the window is now under the podium toolbar).

Thanks,

John DeSoi, Ph.D.