I believe that CDD 1.1 and Chemdog IBL are the same and based around the ChemD cut. The C4D is a mix between The Chem4 cut and ChemD. These were Rez's versions of the clone onlys that he tried to take to seed form. The 1.1 came out because people were complaining about the IBL so he through out the 1.1 which was supposed to be another version of the IBL for ChemD. Thats what I remember. The real clone onlys of the chemdog strain are chemD, chem4, 91chem and chem sis. They are all different and the 91 and chem sis are harder to find.
The Chem 4 D was the chem 4 cut x rez's Chem D IBL. The Chem D IBL has been grown and shown by a few ppl here with decent results. The V1.1 well I have actually never seen even one single picture of this strain, so it either sucked or no on has ever grown it. The lineage of the V1.1 was never actually said just speculated but I think Rez said it was a continuation of the IBL to lock in more of the D traits.
FWIW The chem 4 is the cash cropping chem, its the one known for the biggest yields then crossed to the chem ibl it should maintain a super stink, good resin and large yield, really probably cant go wrong with that one.