Sleeping Bag: Mont Bell Ultralight Super Spiral Down Hugger #3 Comfort rating 4 C (EN)
Sleeping Mat: Sea to Summit Ultralight Insulated Sleeping Mat R3.1
Liner: Sea to Summit Reactor 8C
Tent: Tarptent Double Rainbow
Wore:
Icebreaker Men's BODYFIT200 Base Layer
Icebreaker Men's BODYFIT260 Base Layer
Icebreaker Men's BODYFIT260 Apex Leggings
Mont-Bell Plasma 1000 Down Jacket
Woke up a few times during the night as I was cold, including at midnight when I checked the temperature and it was 8 C, so you could say I am a cold sleeper

Typical Winter Camping here in WA sees the temperatures getting down to around 0 C at night in the outback
Options:
[1] Can I get away with adding a "warmer" Sea to Summit Thermolite Reactor or am I kidding myself?
[2] Face up to a new sleeping bag. I do a lot of bikepacking so pack downsize is critical as is the weight [hence excludes quilts as an option]. I am thinking a Sea to Summit Spark SP111 with a comfort rating of -2 C [$520] or a Therm-a-Rest Hyperion - 0C comfort rating [EN] [$567] or maybe a Sea to Summit Spark SPIV at -8C comfort rating [EN] [$630].
Thoughts?