Line scaling in Illustrator CS6

Hi everyone,

I'm attempting to Illustrator CS6 to digitize a series of surficial geological field maps and I'm having a couple problems with brushes and proportionality (forgive my terminology), any assistance would be appreciated.

The standard annotation from the USGS for a landslide scar (scrap) is simple line with a series of evenly spaced hatches.

If i make this into a art brush (drag and drop into the brush toolbox) to apply to lines etc digitized with the pen tool the spacing and sometime size of the hatches is dependent upon the length of the line.

Is there a solution to this problem whereby the size and spacing stay consistent regardless of the lines total length? I've experimented with the Brush Scale Options in the Art Brush Options but that doesn't achieve the desired result