With all new parts, 1/16" is probably OK, as they wear, 1/8" will be good. The point of toe-in is so under driving conditions, the tires are still close to parallel when going down the road. Rolling the tires forward with full weight on them is needed for a true measurement, don't use the brakes to stop, and don't let it roll backwards, both of which can change the measurement. Does it really matter? probably not, no alignment shop I have been in rolls them, but it's the most accurate way.
After a few 100 miles of driving, check it again along with the tire wear.
