Buy Canadian. The MagWedge rails are lower profile and an awesome product.
Full length rails give you more options down the road if you want to scope it.
But if you're going with just a red dot, track down a BC Tactical mini rail, that just replaces the rear sight. Leaves the receiver open for stripper clips, and is an easier install - or so I've heard. I don't have any personal experience with them, but they're quite well thought of. I'm tempted to get one just to throw my Vortex Spark on it. (The spark is currently attached to a rifle that I just don't shoot much, so it's a bit of a waste of a nice optic). This would involve sneaking another SKS into the house... Once in the house, I'm fine, because my wife has already lost track of the # of rifles I have, and they all look the same to her.
http://www.bctactical.ca/products.html