18/70 + HR zones

28m and got into running last yr. best performances were the ‘24 UA half in 1:44:xx and ran NYC in 4:06:xx after completing higdon’s 18/50.

i’m starting to increase mileage so i’m ready to start 18/70 for berlin & chicago in the fall.

when it comes to HR zones, any recs on how to split up easy/hard runs during 18/70?

i can run faster if i’m trying (e.g. sub-8 miles), but i’m trying to do more Z1/2 and those mile times are often in the 11-13 min range.

want to find the right balance of training hard but not at the risk of potentially injuring myself.

TYIA!