Emailed you an update. Added:
DefinePaintbarParameter(String ParameterID, string ParameterDescription = null, Boolean IsInteger = false, Double Minimum = 0, Double Maximum = 100, Double Increment = 1, Double Default = 1)
Double GetPaintbarParameter(String ParameterID)
Just use DefinePaintbarParameter to define it, then GetPaintbarParameter to get the user specified value