Rag Joint Instllation Help Needed

[Porkchop]

I searched for this but did not find anything. MY engine kit came with backer plates for the rag joint. Common factor. Mine came with a 2 piece and a 3 piece plate assembly. Is one of the metal backer plate assemblies supposed to go between the rag joint and the rear sproket/gear ? I know one of them goes on the outside of the rag joint that goes around the rear hub between the pokes. If I need to use both sets of backer plates, does it matter which one goes where. If I only need to use one, which obviously would go on the inside on the wheel, which one do I use there, or does that matter !
I did a dry fit yesterday and used a backer plate between the rag joint and the rear sproket. Centering the sproket was not a problem, but to get it straight/flat was impossible. I'm thinking that might be beacuse of the backer plate between the sproket and rag joint. Any and all help/answers/suggestions will be greatly appreciated.
Thanks.........PC