The cheek weld (or lack there of) is notorious. Some shooters find them nearly unusable. Thankfully, Echo Nine Three has a solution – the UFCR or Under Folder Cheek Rest.
The UFCR is simple and I mean that as a compliment. It is a molded, .08″ thick Kydex piece that snaps into place between the two bars of the under folding stock. It provides a more repeatable and comfortable cheek weld for stamped/AKM under folders including the Yugo M70. It must be removed if you fold the stock but installing/removing it is easy.
Check out the UFCR at Echo93.