I think Dirla is incorrect.

I have this spur myself and it uses 3/32 diff balls for certain.

Straight from the liked website above

"This is an optional CRC 64 Pitch, 72 Tooth, 16 Ball Pan Car Spur Gear. This spur gear uses 16 3/32" diff balls rather than 6 to 12 1/8" balls. This is done to reduce weight and maintenance by increasing the surface contact area, so less tension is needed on the diff nut to keep the diff from slipping. "

It is ok if the balls fall through. They do not snap into the spur like the kimbroughs do. Roll the balls through some 6636 ae lube before placing them in the spur, or build it on top of the inner diff ring half assembled on the axle.