Some Ideas On Balancing Left and Right Brows

A friend told me some artist who does brows embroidery without drawing shapes (no left nor right side). The final product is stunning because left and right both look similar. I wonder how such thing would be done, so here are my thoughts on how one can achieve that kind of result.
1. Hair stroke length: Make sure one stroke is consistent and as long as the NEXT stroke. The emphasis here is NEXT!
2. Hair stroke displacement: The distance from stroke #1 and #2 is consistently as long as the distance from #2 to #3, and so on. In other words, the gaps between the hair strokes should be similar, say 1mm for the sake of argument.
3. Starting point: You have to choose a consistent starting point. Let say you choose the starting point at the brow's head, so from this point to the last point of the tail is the length of the brow.
4. So with the 3 points listed above, you try to achieve consistency for one side of the brows, say the Right one.
5. Now switch to the Left brow and repeat the same things like you do for the Right brow.
6. After you're good with item #1 through #5 above, try to achieve the consistency between the Right and Left brows. To do this, I suggest the following.
-- 6.1 Count the hair strokes on each side. Suppose you got 40 on the Right and 39 on the Left, you error is 1mm (that is, the Right brow is 1mm longer than the Left).
-- 6.2 Cut the displacement in half, say from 1mm to 0.5mm. If you now have 40 on the Right and 39 on the Left, you error is only 0.5mm (that is, the Right brow is now only 0.5mm longer than the Left)
-- If 6.1 and 6.2 above can't be achieved, use a ruler to mark the starting point and the ending point on each brow. Make sure the length from starting point to the ending point on the Right is the same as that on the Left. It's a compromised method to assist you, like a prop if you will.
I don't know how long it would take you to get to where you don't need to draw shape on both sides, but here are a few thoughts on my part. It's a tall order, but it's worth trying. What do you have to lose? :)
DN