Can "almost" help you.
Have a .177 200T. This U.S. version is marked AA 200T and is marked 16J.
Have a .22 AA s200. It's also marked at 16J.
Everything on the inside (spring/striker/air passages) is identical.
There are other versions (more common outside the U.S. (but here as well) that were marked at lower energy (7.5J?) that do have internal differences.
So I'm going to assume the one in your hands is the US version of the 200T that is marked 16J (normally on the right side of the reciever, where the barrel connects).
Assuming you have the 16J marked version, I'd try that "strangle screw" (which is actually a air flow restrictor screw for the transfer passage).
Think of it this way: the striker spring adjustment sets the range of pressure that the rifle runs best in....the strangle screw sets the amount of air reaching the pellet.
On the 200T at hand, have it set for a nice shot count at 12 foot pounds. BY just turning the restrictor screw in, will shoot at 7 foot pounds (and a longer shot count).
Works over the same fill pressure rnge (the striker spring adjustment isn't changed), just either letting more air reach the pellet.
Your post shows you DO NOT have one of the other versions, but will mention them anyway.
Some were/are made for places with more paranoid/restrictive air gun rules, that were made non-adjustable ("tamper proof"). On the ones I've seen, they didn't slot the striker spring adjustment, glued it in place, and either never drilled for the air restriction screw or rivited over the hole.