The following options will be created in the GameUserSettings.ini file once you've at least equipped a pair of the Single Player Scissors and logged off. You can also add them manually before you start your game (settings only take effect if you change them while the game is not running). The values listed are the default values.

[SP_Scissors]
HeadHairLocksPerPercent=200.000000
FacialHairLocksPerPercent=100.000000
HeadHairCutDurabilityCostPerPercent=-1.000000
FacialHairCutDurabilityCostPerPercent=-0.500000
MinCutDurabilityCost=-0.010000
AllowPositiveHaircut=False
DyeHairColorSaturation=0.735000
OnDinoItemDurabilityToSubtract=-0.500000

HeadHairLocksPerPercent controls how much hair is returned when adjusting the slider for your "head" hair. 200 seems to be the maximum for me. You might be able to get more if you have a mod that increases the stack limit of Human Hair. Let me know if you try this.

FacialHairLocksPerPercent controls how much hair is returned when adjusting the slider for your facial hair. Works for females too even though you don't see a beard.

HeadHairCutDurabilityCostPerPercent controls how much durability is removed from the scissors when you cut or grow (see below) head hair. I think fractions get rounded up.

FacialHairCutDurabilityCostPerPercent controls how much durability is removed from the scissors when you cut or grow facial hair.

MinCutDurabilityCost controls the minimum durability cost, presumably. I haven't tested this setting. I would think that if this was set higher to one of the durability settins above then this would be the durability cost. Let me know if you try this.

AllowPositiveHaircut controls whether or not you can grow hair by moving the slider (head or facial) to the right. Setting this to true would allow you to grow and cut your hair to your hearts content.

DyeHairColorSaturation. I have not tested this. Presumably controls how dark or how light the color is when you dye your hair.

OnDinoItemDurabilityToSubtract. I have not tested this. Presumbaby controls the durability cost when using the scissors on a dino (e.g. Ovis). Value is probably round up to the nearest whole number.