If you extract slowly it's quite even, no bad tendency. If you try to go too fast, especially with the high power heater you can get a hot spot at the center and if not you still get a clear gradient where the exposed face gets dark and the material deeper under is still green. But that's the case with all my convection vapes.
You can definitely char with both heaters when not careful and the exposed face can get dangerously close to black. I don't like flirting with combustion personally, so when it happens I'm a bit gutted. It spoils the taste for the remaining of the session.
With the dual screens method and the low power heater, I'm very satisfied with the evenness. I like to stir the bowl once before the end, but that's because I'm doing on average 120mg loads, sometimes a bit more. It's not necessary to stir but it helps to preserve taste until very late. If you don't stir, in order to fully extract the part that is away from the heater, you get the part facing the heater exposed to too much heat and it has to get darker than I like.
When microdosing I don't think you would have to stir at all. The shallower the bowl the better.
As for the material color at the end, I believe it's not a good indicator. With all my convection vapes the material is considerably lighter than with my conduction vapes. If they were really extracting less than conduction ones, then why would I feel much more medicated with them?
I didn't try very often but I remember back then when I got my first Zion that I tried finishing the load in a conduction vape at max setting, to see if there was really something left, and it was super disappointing. A couple tiny wisps with awful taste were all I got, not worth the effort IMHO.
EDIT: now that you made me think about it, in retrospect, there are probably other explanations why these on-demand convection vapes seem to medicate more. And the color argument might be entirely in my head. It's also clear that it's harder to extract at super high temperatures with these unregulated vapes, because to get there you risk combusting at the very first mistake, whereas a conduction vape can safely get you right to the limit, as their temperature is always *at or below* the one displayed on screen (due to the bowl thermal conduction coefficient, which is pretty obvious with ceramic ovens) Also when I used conduction vapes a lot, I tended to do temperature steps and for the last one there wasn't much left too...
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, so I say go for option 2, it looks good enough to eat, like a tiny little bento box. 
