You ruling was correct - advancing runners are allowed to round the base, pause for a brief moment (your judgment), then either advance or return. The ball in the circle is not a magic stop button. This information is interpreted in the Rim that they hand out at LL Rules Clinics.
As for what rules to use filling in gaps?? LL rules are based on OBR with safety modifications and softball differences. You could probably get away with applying ASA interps without many problems - although some purists will probably state otherwise
