Originally Posted by
urbanknight
...I don't understand all these "mtb....
I'm with you. I take "can't work" and "won't work" as a challenge
I step back and consider what would be needed for it to work, ie. slightly more chain take up. Than figure out how to make that happen.
This comes more naturally to me because I started serious riding before the internet or product documentation, so every build involved working from a blank slate.
To the OP
Challenge yourself to tinker until it works for you. The only serious sin is cutting the chain too short so measure 3x first if considering that.
If you want to see if a larger idler will help before buying one, jam something between the chain and puller to increase diameter where the chain leaves. Test the effect at both ends of the idler cage arc.
Likewise with B screw. Jam a small wad of paper between the screw and tab and see if it helps. if so, buy a longer screw or modify the stop tab.