Nobody can tell you on timing. You're fighting:
- timing on sales
- availability in the lowest fare classes for F cabin
- availability for three tickets
ITA Software's Matrix fare search is very good and powerful/flexible if you have flexible dates and/or length of stay. Find what looks good with Matrix then book it on delta.com.
http://matrix.itasoftware.com/
Are you sure you don't want a non-stop on Hawaiian, Alaska (SJC or OAK), or United?