AutoCAD LT :: Change Linetype Scale For A Layer?

I want to change my ground conductor from solid green to a dashed line (green is OK) on a set of drawings, but all the dashed linetypes I can find don't show up well at the scale that I've drawn the circuits.  I can make them look OK by changing the linetype scale in the properties manager window, but there are a boatload of these lines in eight viewports; finding them all would be a major pain.  They are all on a single layer, though, but in the layer properties manager I do not see a way to change the linetype scale for the layer. I could use the properties manager to make the change if I could select everything on the layer. Is there a way to do that?