Nightcrawler, the Ultimak made for the Yugo is made to allow the grenade sight to fold normally, the UTG quad rail is #1 a full 1 inch to short, the upper rail would need to be cut short and the Yugo barrel is thicker requiring ya to mill out the inside of the lower HG even after ya have fabricated spacers to account for that 1" length difference..
You can get a side rail on the cheap by ordering from Tickbit supply the UTG Copy of the Russian MTK02 for $9.99 its actually made better than the original, you can either rivet it on or drill and tap the holes for screws and install button head allen screws from the inside of the receiver, how long it take to install depends on how long it takes you to drill 3 holes..
its cutout for trigger and hammer axis pins so positioning is a no brainer, lay the rail on the side of the receiver, measure from the top rail on the receiver to the top of the side rail (NOT the backing flange but the rail itself) get both ends level and mark your holes, you can actually get by with just the two end holes, now drill your holes and install the screws, I'm setup for riveting guns together so rivet mounting the rail is my preference but no real difference if the screws are lot tited....
Thats the correct way to add an optic to an AK, plus if ya get extra side mounts (get the low profile Russian with weaver rail) you can setup and sight in each optic ie; a red dot on one a low power fixed magnification scope on another and a variable high power on yet a third all will swap in under 2 seconds and hold perfect zero......... can't do that with a scout mounted optic,
Anyhow I just got home and needa get settled in someone just e-mailed me this so figured would get it answered Nalioth or someone can give ya the links for tickbit supply and Kalinka optics Tantal source for rails already setup as screw mountable (more expensive) etc.... I needa get a water line fixed that froze while I was away.......