Well i managed to find an oil restrictor here in the U.S. I got it from XS Engineering, only 10 bucks plus shipping! However, if you want to make one, the OUTSIDE diameter is 6.12mm and the height is 5mm. Obviously the INSIDE diamter is going to be 1.5mm. Also, one end has a slight taper to aid in starting it in the block. Thought you guys might want to know.
Brandon