HI Panics, Just noticed your an Aussie. Hi Mate.
I would think a 0°F incubator will be too much for most of your use. (Not quite sure where you are located though)
If the plan is for mostly above freezing stuff and even below just get the 3s incubator with maybe a little overfill. Even that will probably be too much warmth here. If it's forcaste to be heaps colder just add a small torso CCF pad to boost the UQ if required.
I've never owned a FL incubator but have owned 3 full sets of HG quilts now. My 3s set rarely comes out unless it's a snow trip. Had my 2oz overstuffed phoenix to -7°C last year and was still very warm (ie; no where near the quilts limits) These quilts are pretty darn good and the rating isn't a science. Depends on how you sleep now ?? Are you a cold or warm sleeper ??
The 3s might save you some pack space and weight. For 99% of your trips the 0°F incubator might just not be needed.
I am a GEAR JUNKIE
and GRAM COUNTER
There, It's out. I said it, Ahh I feel better now