Thanks!
Yes, I did change BaseLightmass.ini the same way I did in UE3:
[DevOptions.StaticLightingProductionQuality]
NumShadowRaysScale=8
NumPenumbraShadowRaysScale=32
ApproximateHighResTexelsPerMaxTransitionDistanceScale=6
MinDistanceFieldUpsampleFactor=5
;NumHemisphereSamplesScale=8
NumHemisphereSamplesScale=64
;NumImportanceSearchPhotonsScale=3
NumImportanceSearchPhotonsScale=24
;NumDirectPhotonsScale=4
NumDirectPhotonsScale=128
; Decrease direct photon search distance so that we will have more accurate shadow transitions. This requires a higher density of direct photons.
;DirectPhotonSearchDistanceScale=.5
DirectPhotonSearchDistanceScale=.1
;NumIndirectPhotonPathsScale=2
NumIndirectPhotonPathsScale=4
; Need a lot of indirect photons since we have increased the number of first bounce photons to use for final gathering with NumImportanceSearchPhotonsScale
;NumIndirectPhotonsScale=8
NumIndirectPhotonsScale=16
NumIndirectIrradiancePhotonsScale=2
; Decreasing the record radius results in more records, which increases quality
RecordRadiusScaleScale=.25
InterpolationMaxAngleScale=.75
IrradianceCacheSmoothFactor=.75
NumAdaptiveRefinementLevels=3
AdaptiveBrightnessThresholdScale=.25
AdaptiveFirstBouncePhotonConeAngleScale=2.5