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Typical NTC thermistors have 3.8% per degree at 20C, ten times the tempco of platinum. So put one of those in the upper arm of wheatstone bridge to do temperature compensation, sort of?
What we really want is to sustain constant delta-T relative to ambient air temperature, since that temperature difference is what drives heat flow and thermal equilibration.
If we want resistance twice ambient, how hot is that? Around 180C! So: if we servo to constant resistance on hot wire, even if ambient changes by 20 degrees, delta-T between hot wire and air only goes from 160C to 180C, not a large difference.
We can just measure air temperature and correct for delta-T.
So:
1) measure IV curve of hot wire device, not to exceed 50 mA. Find excitation current where resistance is 2X that of ambient no-heating value. Should be around 30-40 mA Be sure to correct for lead resistance in series!
2) set up op amp circuit to maintain constant resistance on hot wire sensor, at optimal bias level.