Belarus BP-02
Personally, I don't like red-dots or scopes mounted in the "scout" position above or in front of the rear sight. I don't like the balance of the rifle or the look of it.
As far as I'm concerned, the best scope mount for a Saiga is the Belarus BP-02. I just ordered one off eBay from a seller who listed his location as the Russian Federation. When the mount arrived, it had been shipped from Belarus, Minsk. It took a little over two weeks to get but it's the real deal. I've used them before and they are low mount and hug the receiver cover tightly. You'd have to remove the mount to remove the receiver cover but they hold zero nicely when reinstalled as long as you're not yanking on the scope or red-dot when you remove them. They come with a weaver mount that your red-dot should mount right to. They also align the weaver rail directly above the top of the receiver, not slightly off center like some others. A russian mount for a russian gun. They are considerably cheaper than the mount listed above in the other response.
Kalinka Optics makes a very similar one but doesn't have pins in it for additional stability. I paid around $54 for mine including shipping.
I've had them in the past, they're great mounts.
here is the old eBay ad of the mount I bought, I hope the link still works:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&item=150306668059
Mine is the low-rise pictured in the two "blue" pictures and mine say Belarus BP-02 on them (in russian it looks more like bn-02)