The grub screws should fit in dimples. When you pull the trailing arms you will see. The arms need to fit on the springs just so. When all the springs are present and accounted-for, there is no way to get it wrong. But if you remove the small springs, and are stupid and careless (like me) you can get the arm on there wrong. Then you gotta hammer it off. I used a two pound sledge with a piece of 2x4 as a shield. Two or three whacks.
I am told that very hard driving can do this to the arms as well (again, if the small leaves are removed). For this reason, the smart and very careful (racer-type) people fill the space left open by the departed small torsion leaves with either A. cut off bits of torsion leaves or, B. something metal that is the same size.
The good news for you: If you have a couple of wracked torsion arms, chances are good you can just put them back on right and forget about them.
Good luck.
Oh, nice pipes!