Actually, still no dice. I copied/pasted the checksum from the modding pack then followed your method.You can grab the original Checksum on my file server HERE.
And I just checked that MegaTitsBase_CastFixed mod. In order for it to work, you have to copy/paste in your WIN32 directory the 28f5bcaec242bee73e0f8cc91d2719da file which is located INSIDE the FIX folder and the fcda0a767217bfb594540040e37679d6 file which is located OUTSIDE the FIX folder.
EDIT: is this mod only compatiable with cast race? i think the character I'm trying it on is dewman. If so, is there still a mod for other races?