If you let them go, you might see another (albiet smaller) round of hops. The best luck I've had with second harvests came from training some but not all of the new laterals up a new string. I'd pinch off one side of the two laterals that are growing from an old leaf node at the bottom of the plant. Do this on three or four of them and then cut back all the other new growth. This way your chosen bines get all the gusto. If you have the means to run a new string, then do it, because the new vertical growth will have a tough time going through the already established bines. And if you're going for another round of hops, then consider feeding them again.
I'm in your area, and have had several seasons of second harvests when the first harvest happens before mid-July. Good luck.
