If I understand the problem correctly, Opera cache is accumulating in pup_save.
I had a similar experience with firefox, as discussed in thread Cleaning up needless cache data in pup_save.
My ultimate solution was to tell firefox to put its cache in /tmp - recall that Puppy cleans /tmp at shutdown, and never saves /tmp data into pup_save.
If Opera can be told where to cache, the same method can be applied.
