ZWO 1600mm + EFW to eos connector

[immy]

Hi all

Recently just decided to get into mono imaging whilst using my existing canon lenses. I have bought a ZWO 1600mm with 8 position EFW. The connector I have (T2 to EOS) works without the EFW attached, which is fine for a colour camera but with the EFW the back focus is too much. Rather than buy a new connector I'm hoping I can use my existing EOS connecter with a smaller space in between. I know the camera end is a T2 and the lens end is the EOS but what I'm wondering is if anyone knows what the size is in the middle of them