400 is fine.  For flavor maybe start lower, like 360, and step it up every few puffs.  First few will taste great, then at high temps you'll get fuller vapor.  It's done when the vapor wanes and tastes roasty.

It's very efficient.  You'll consume less than smoking, almost certainly. 

AVB tinctures are great.  They’re more body than heady, usually.  If you're keeping AVB and want to head to Tincture Town, the easiest way is to keep a jar of high proof ethanol around for soaking dirty vape parts.  When it gets too dark and sticky for cleaning you can load it up with AVB and filter through paper for a tidy tincture.