1/8 of total toe is plenty so I really don't think you need that much toe. You can measure it easily on one side by setting the other side to zero toe by turning the steering wheel to get your measurements to be the same at front & rear of the wheel rim edge. The other side's measurements will tell you the total toe. The steering rack "automatically" halves the toe for you when the steering self-centers itself upon driving the car.
Good discussion here
http://forums.pelicanparts.com/porsche-911-technical-forum/297155-how-measure-toe-out.html regarding toe measurements and I should correct myself by saying that your wheel diameter is important when measuring toe