To try out these alternative cast iron nether fences:

Drag a copy of the nether fence of choice onto the desktop. 
Rename to '1.png'
Drop it into the 'GlimWoodWork' folder in the 'ctm' folder in the pack.
Allow it to overwrite the existing '1.png' file already in there.
Close the zip and see what your chosen alternative cast iron nether fence looks like in game.

~Glimmar
