Re: good hi-capacity SKS magazines/drums
focusmaniaczx3 you have pretty much answered your own question when it comes to Hi Cap mags for the SKS,99% of all those after market mags are just pure junk and do not work,If you feel inadequate with the ten rd. box mag and stripper clips your best choice is the Tapco 20 rd mag. and your stock will have to be modified in most cases to accept it because of the difference in the mag width,it gets a little fatter especially when loaded.
The drum if you ever find one may work but be aware it will probably cost you about as much as your rifle did at todays prices,also because of the design your rifles stock may have to be modified to accept the drum. Also the original box magazine is one of the original imported parts on the 10 rd. fixed mag SKS rifle once you remove the original mag you fall under 922 and your required by law to remove and replace a certain # of other imported parts with US MADE part to have a legal rifle.
My 2 cents if you want Hi Cap mags that work,keep the SKS like it is and by an AK,by the time you buy all those mags or a drum and compliant parts you could buy a nice AK.