Why are you running at such a low temperature?
Propylene glycol/Boiling point:
370.8°F
188.2°C
And VG boils at a much higher temperature. You can google it. At 350 degrees I don't see how you are getting much vapor at all.
the boiling point of vg and pg are well known, when i see people vaping at 350 F it makes me wonder.
Both glycerin and propylene glycol are hygroscopic, and they will absorb water from the atmosphere. This dramatically lowers their boiling points, which is why e-liquid will vaporize at temperatures much lower than you think.