I ordered the kit from Mojosights, $15 delivered.
It comes with 0.090" and 0.120" apertures to replace your stock 0.150" aperture.
I found the 0.090" aperture to be kind of claustrophobic especially with that huge front post in the way... But the 0.120" seems to work very well with the front post.
Is there a favorite aperture size for the Mojosight on the AK/SKS?