The umbrella action produced by the core construction of Barlow's Umbrella Lunker Skirts produces great "Spider Type" skirts for spider jigs.  It is very simple.  Trim the strands on one end of the umbrella skirt to about 1/2" from the core.  The strands on the trimmed end will flair out from the core.  If you want to add some action trim a few skirt strands on the other side of the core.  That's all there is to it.  The skirt is ready to put onto the jig head.