I made a custom cas screen-saved it as you are supposed to, moved the lot to the bin, grabbed the last lot that was placed in there (the number will be
1 higher than the Cas lot you put in there) changed the name and put it in the NL Global Lots folder (or whatever the highest exp is) then I just deleted that lot (and the previous numbered lot too) from the lot catalog folder. When I next went in game all was as it should be.