I went to the pattern board and found that I want to change my M2 to see less rib. I read my owners manual and if my memory is correct I have X,A,B, and C shims. B was installed and if I understand this correctly C should change my sight picture to see less rib. I have read of a D shim. Is that for the M2 and SBE2? Also I have read that the SBE2 C shim is the old SBE D shim. Is that correct? What available shim will allow me to see the least amount of rib? It also pointed slightly to the left but I am right handed and my understanding is that there is only one shim for cast and I have the correct one installed. Any help is appreciated.