did you find any solution for the "big" TIFF-Files created with plugins in Aperture?
I have been using Aperture and the Nik pluggins and have read about this on other forums also. I believe that since Aperture must export as a TIFF to the Nik software, that is why the plug ins send back a TIFF file. As was said, you just have to export as a full size JPEG, save that back to Aperture and delete the TIFF file. A bit of an annoyance, but as far as I know that is the only way to get rid of the TIFF file.