Try 0.30000, for example.
[OpenGLDrv.OpenGLRenderDevice]
RefreshRate=75
DetailTextures=False
UseTrilinear=False
UseS3TC=True
UseTNT=False
LODBias=0.000000
UseMultiTexture=True
UsePalette=False
UseAlphaPalette=False
Translucency=0
VolumetricLighting=False
ShinySurfaces=False
Coronas=False
HighDetailActors=False
MaxAnisotropy=0
Alwaysmap=0
UsePrecache=False
SupportsLazyTextures=0
SwapInterval=0
GammaOffset=1.000000
GammaOffsetRed=0.000000
GammaOffsetGreen=0.000000
GammaOffsetBlue=0.000000
TruFormMinVertices=0
TruFormTessellation=3
UseTruForm=False
ZRangeHack=False
AAFilterHint=0
NumAASamples=0
UseAA=False
RequestHighResolutionZ=True
MaskedTextureHack=False
FrameRateLimit=0
UseVertexProgram=False
UseCVA=False
UseMultiDrawArrays=False
TexDXT1ToDXT3=False
DynamicTexIdRecycleLevel=100
CacheStaticMaps=False
UseTexPool=True
UseTexIdPool=True
UseSSE=True
BufferTileQuads=False
BufferClippedActorTris=True
SinglePassDetail=False
SinglePassFog=False
ColorizeDetailTextures=False
DetailClipping=False
UseDetailAlpha=True
DetailMax=0
MaxTMUnits=0
NoFiltering=False
NoMaskedS3TC=False
Use16BitTextures=False
AutoGenerateMipmaps=False
AlwaysMipmap=False
ShareLists=False
UseBGRATextures=True
UseZTrick=False
MaxLogTextureSize=8
MinLogTextureSize=0
MaxLogVOverU=8
MaxLogUOverV=8
OneXBlending=False
GammaCorrectScreenshots=True
DescFlags=0
Description=