26ga*2 would be pretty much a 0.4*0.8mm (minus the rounded edges), very similar to the 0.3*0.8mm one (with less rounded edges), and both are wrapped in 32ga (0.2mm).
I wanted to try the flat+wrapped approach for increasing the coil's juice-touch/surface ratio, and both wire types are offered at the same price ($1.79 per 15ft), so I don't know which one to take, plus what to await in terms of power consumption (SS316L). The simple non-wrapped flat wire has substantially less sex-appeal ^^
You comparing the width of the core? With a Clapton type coil you have to take both the core and the wrap into consideration. The wrap contributes to the overall mass of the coil, so the lower the gauge, the higher the mass the more power is needed and the more time is required for the coil to cool down.
We all have our own values and preferences when it comes to Clapton type coils, but personally I feel the wrap should contribute little to the overall mass.
Example using one of my SS316 Fused Clapton’s
2x 28awg with a 40awg wrap. 7 windings around a 3mm ID = ~190mg in mass
2x 26awg with a 32awg wrap 5 windings around a 3mm ID = ~480mg in mass
The 2 coils are roughly the same size but one is more than double in mass and will require a significant amount of power