Hey Nick,
I wasn't able to get this to work in the percent complete column, but in a status column, I was able to get the complete & 100% grey (white wouldn't work), and the not complete & 100% red with the standard rules:
It was super finicky and if I made changes to them after creating (I forgot to apply to the entire row), it stopped working, not sure why.
Here is the text mode:
enumclass=com.attask.common.constants.ProjectStatusEnum
linkedname=direct
namekey=status
querysort=status
styledef.case.0.comparison.icon=false
styledef.case.0.comparison.isrowcase=true
styledef.case.0.comparison.leftmethod=status
styledef.case.0.comparison.lefttext=status
styledef.case.0.comparison.operator=in
styledef.case.0.comparison.operatortype=string
styledef.case.0.comparison.righttext=CPL
styledef.case.0.comparison.trueproperty.0.name=bgcolor
styledef.case.0.comparison.trueproperty.0.value=e8e8e8
styledef.case.0.comparison.truetext=
styledef.case.1.comparison.icon=false
styledef.case.1.comparison.isrowcase=true
styledef.case.1.comparison.leftmethod=percentComplete
styledef.case.1.comparison.lefttext=percentComplete
styledef.case.1.comparison.operator=eq
styledef.case.1.comparison.operatortype=double
styledef.case.1.comparison.righttext=100
styledef.case.1.comparison.trueproperty.0.name=bgcolor
styledef.case.1.comparison.trueproperty.0.value=eac6c9
styledef.case.1.comparison.truetext=
textmode=false
type=enum
valuefield=status
valueformat=val
row.0.styledef.applyallcases=true
row.0.styledef.case.0.comparison.icon=false
row.0.styledef.case.0.comparison.isrowcase=true
row.0.styledef.case.0.comparison.leftmethod=status
row.0.styledef.case.0.comparison.lefttext=status
row.0.styledef.case.0.comparison.operator=in
row.0.styledef.case.0.comparison.operatortype=string
row.0.styledef.case.0.comparison.righttext=CPL
row.0.styledef.case.0.comparison.trueproperty.0.name=bgcolor
row.0.styledef.case.0.comparison.trueproperty.0.value=e8e8e8
row.0.styledef.case.0.comparison.truetext=
row.0.styledef.case.1.comparison.icon=false
row.0.styledef.case.1.comparison.isrowcase=true
row.0.styledef.case.1.comparison.leftmethod=percentComplete
row.0.styledef.case.1.comparison.lefttext=percentComplete
row.0.styledef.case.1.comparison.operator=eq
row.0.styledef.case.1.comparison.operatortype=double
row.0.styledef.case.1.comparison.righttext=100
row.0.styledef.case.1.comparison.trueproperty.0.name=bgcolor
row.0.styledef.case.1.comparison.trueproperty.0.value=eac6c9
row.0.styledef.case.1.comparison.truetext=
Hope that helps!