Okay folks, I had some time to check some things on the XS. Here is an update.
Charging System
Rotor: 5Ω between slip rings, no grounding between housing ✅
Stator: White-White 0.4Ω on all combinations, Yellow-White 0.2Ω, and White-Ground infinity ✅
Regulator: Ground-housing 0Ω, Green-Brown...