I also picked up a used Saiga .308 on the cheap.
It needs lots of work as you describe.
I moved the fcg forward. Sold the old tg, fcg and polymer furniture in the
marketplace. I went with the RSA milled AK fcg.
Milled my own lower hg. Added a Tabuk flash hider.
I also have since added a mini-Versapod to the forend.
It it now worthy of becoming a weapon.
Is highly effective out to 300 yds.
Shoots like a sniper rifle. (as if I knew what that was)
It was a fun project.