1985 MAGIC CHEF LP GAS FURNACE ... model # G6A750-11 SER.# A-15283E AB ? 75,000 BTU Can u help me ?

My 1300 f² renovated house uses a heat pump for primary heat in Maine. I kept the temp abt 68° in the main part of the home during the day and 60 at night. There is a full basement which I installed insulated 2x4 walls (2" iso and s/r) for most of it. I also installed a Rinnai EX38CT gas vented heater in the basement that I ran at 55° full time last winter. I had an deficiency company add attic insulation and tighten the house up with other improvements like foaming the sills, many new windows and doors. I'm wondering if that is the best way to manage the heat? Would you change the basement heating cycle or temp from full time and 55°? Any other ideas for heat savngs?