On this particular target, I stacked using DSS and chose 2x drizzle to see how it worked. I've tried changing the pixel size by 2x or dividing by 2, but neither helped. Usually, I don't use drizzle in DSS. I tried a different target and stacked with DSS without drizzle and was able to get SPCC to work as long as I used the online database. Still can't get it to work using local files. I've set Gaia prefs to use the the files I downloaded from the PI site. I have the first 5 DR3 files and the first 10 DR3SP files from the full set. They are in separate directories on my hard drive and are selected in Gaia using their respective dropdowns. I don't know what else I need to do to get it configured properly.
This used to work without a hitch using the local files. At that time, I only has the first DR3 file and 3 DR3SP files from the small set (I think).