Yes... Use your 20 yard pin. Keep focusing on the 20 yard pin from 10 yards and also 30 yards and you'll be able to do the "walkback" tune method.

Edit: Aim at the exact center bullseye of the target with the 20 yard pin (from 10, 20, and 30 yards). That way you see clearly see the pattern:
.....o.....
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.....o.....
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.....o.....