I went to many gun shows and gun stores trying-out aftermarket SKS stocks. I figured out that the RamLine fit me best, but YMMV.
There is no substitute for trying-out the stock. Some things require first-hand experience.
I would suggest, if the user intends to wear body armor, that some users of the SKS might be better off with original Length-Of-Pull, instead of going longer, what with the added bulk of the body armor.
It's easy enough to cut-out plywood spacers for syn stocks that are too short. Much harder to cut down a stock and have the OEM metal still fit.
Pachmayr makes some slip-over butt-pads, which extend the LOP, but getting the size right for the SKS is a pain. Sorry, I don't recall which size.