Larry, I have been tinkering with making perfect jig and pig combo for about 10 years. I first started covering the jig head with felt to help with skip casting under docks. The felt gave the sparky lead head more surface area, added benefit of ultimate scent retention and lifelike hairs of crayfish. It was great won 11 of 13 local bass tournaments with two second and several big fish pots. With progression took the felt or leather and made a tail added to sparky lead head. The shape of the tail, more square vs more rounded. Square tail works great in cover like square bill crankbait and tracked straight on the retrieve and with slack line the jig fluttered on the fall. The rounded tail was great for left to right darting on the retrieve and similar with slack line on the fall.
http://i812.photobucket.com/albums/zz43 ... image.jpeg. I tinkered with all the flex rubbers couldn't find the magic flex. it was cool to see the rounded felt tail make jig dart right and left and different trailers along with skirt material and without skirt affected the actions.