The PlanetSize.txt file has 3 different ringworld entries. However, I seem to have changed the "Ringworld" to be "LargeRingworld" in PlanetSize.txt, but not SectType.txt. The problem has gone away! Thanks.
So what would you like your prize to be?
As a note: Extra unreferenced entries in SectType.txt are simply ignored. In the uploaded files, there are "Ringworld" sized planet entries that are not referenced by PlanetSize.txt. This is not a problem. The problem is when PlanetSize.txt calls for planet sizes that do not exist in SectType.txt.
The only Gas Giant None worlds in there are ringworlds and sphereworlds, which exist in stock SE4 as well. They seem to just be ignored by SE4.