Q: Preferred scope mounts - AK side mount or picatinny'd receiver cover?
The receiver cover is too flexible to hold a good zero. For any serious work, get the side mount.
Go with a PSOP side mount Russian scope
http://kalinkaoptics.com/rifle-scopes/posp/ak-vepr-saiga-slr.html
http://kalinkaoptics.com/mounts/ak-vepr-saiga-romak-1-2-slr.html
Do not get a picitinny dust cover. it is not solid.
I would not mount anything more powerful than 4x for a scope.
This is what you want. Original equip.
I have tried some cheapy knock offs and they dont cut the mustard.