Lucky,
Is your attic ventilated? I have way over ventilated my attic with dormer vents .I read in a construction trade magazine that they are much more effective than the turbine type. It’s over insulated too. The house has the sensation of being under a shady tree on hot days and keep added heat in on cold ones. Single storey with large overhangs helps a lot in California. As you say dual pane windows are incredible for comfort and also noise control.
