Drew--the screw is .909" long; .230 wide at the screw driver slot end (with an o-ring--a wide one--directly in front of the screw slot). The thread is .425" in length; .100" in width. The needle stub is about .110" in length and maybe .040" in diameter.

It screws into the base of the carb on the rear SIDE (same side as the choke and throttle linkage.

It does not use a spring to hold it in. It is recessed into the carb base.

Good luck.