Hi anonymous,
I suggest you the DSE-084 model. It's almost same size of a regular cigarette and works fine. Actually i prefer vape my 084s than 510s, even at home. Why? it's cheap, good throat hit and good/clean vapor production.
The only problem i see in 084 (other auto models) is that automatic batteries what keep lighting up on high sound/vibration environments.
It's great to know you have engineer/chemistry experience, as you know, the ecigs technology is kind early yet and need enhancements.
And herbal extracts in e-juice would be heaven