Optimal length for sweet potato vines?

[frdnicholas]

Is there such a thing for the best production of sweet potatoes? I have some growing in beds that have their first leaves and I'm just thinking ahead. I know the vines grow quickly and profusely so I'm just wondering if the length of the vines has any effect on how the potatoes grow?

 

[Meadowlark]

Yes, the more robust vines the better the harvest. Don't prune them but encourage growth.