I was not able to get satisfied with either of the receiver cover scope mounts i tried. The best way is to mount a rail on the side of the receiver & use a POSP type of scope mount. MOLOT SKS Original Rail with Rivets http://www.sksboards.com/smf/index.php?topic=24464.0
Alternatively, there is the Choate mount, but i think it makes takedown more difficult. http://www.sksboards.com/smf/index.php?topic=81857.0
I decided to leave mine optic free for the moment and just switched to a peep sight from tech sights.
There is also a mount that attaches to the rear sight, "scout" style. http://scoutscopes.com/
Of course, if you have the Tapco railed gastube cover, you could put a red dot or a reflex sight up there. (goofy looking, IMO) http://www.sksboards.com/smf/index.php?topic=79490.0