Spoke to a couple of Russian dudes at the gun show. They were selling nothing but AK47, 74’s and SKS’s. Asked what their recommendation was.
Theyski toldski meski....put the SKS back to it's original condition for reliability sake.
Norinco made a "Paratrooper" model that used AK mags and there was an adapter that used AK mags though I don't know how well it worked.
Avoid the 30-round magazines, the spring of which places too much tension against the bottom of the bolt during its travel for the first ten rounds or so. The main reason for going to a detatchable AK-type magazine on a SKS is if you're going to mount a scope on the rifle, which prevents loading it from the top the way it should be done.
For the same reason, also avoid the 30-round fixed-in-place accessory magazines for the SKS. The shorter 20-round versions may give acceptable results, but the extension protruding from the bottom of the rifle prevents the good use of the rifle from the prone position, and turns it into a from-the-hip or off-the-shoulder bullet hose instead of the handy carbine that it is- in its issue form. Most SKS carbines I've shot will outshoot most Ruger Mini-14 rifles I've tried head-to-head comparisons with, given quality ammo. Most of what's available for the SKS is not, though it's reliable enough and okay for a 16-inch barrelled AK.