OK, imagine the jig as you currently have it assembled was made of rubber and now imagine turning it inside out like a surgical glove
ALL the interlocking pieces retain exactly the same positional relationship and still mesh exactly the same way. But now you have right thrust. If you do not at least give a try reconstructing the jig this way then I'm going to conclude that you really do not want to understand....
Hey, why not try this if disassembling the jig is too much trouble. Take a rubber glove, say a right handed one; mark the top/back to keep orientation; turn it inside out. Guess what? Now you have a left handed glove!
Edit: and to help with relevance, the firewall rests against the thumb and forefinger tips and the angle offset is the thrust angle
Edit 2: OK OK, take the existing jig and put a mark on the outside face of each piece. Now assemble it with the marks inside.
Looking forward to extracting my foot if I'm wrong
That''s all I got to give........