A DBV was my first serious vape (my first ever vape was a MFLB. The DBV was after that).
It's a fantastic vape. Though, I've acquired a SSV since then, and I've not pulled out my DBV since then, because the SSV is superior in my opinion. However, I'd still pull out the DBV along side the SSV if I had friends over and we need multiple vapes. I still like my DBV, and have no intention to sell it.
As far as favorite spot on the dial, that can and will vary from vape to vape, and person to person with all these 7th Floor Vapes because 1) every ceramic heating rod is unique and may need a slightly different amount of power to achieve the same temp. 2) the knob can be moved. I know I've removed mine and pressed it back on to change the on/off point to where I wanted it to be at. I've also removed and re-pressed on the knob to have my desired average starting temp at noon. So it can vary. And 3) Each user's preferred draw speed can drastically effect the temp they prefer to set the dial at. People that prefer to draw at higher speeds will want a higher temp setting than people who prefer to draw at lower speeds, for example. But that's not even the only factor. Grind style can effect this, as well as the type of hit and flavor profile you prefer.
I suggest first starting low (less than noon), and see the flavor you get and how high you have to go in order to get the minimum level of vapor production you prefer (experiment with different grinds and draw speeds as well). Then, over time, and when you're in the mood to really crush it, experiment with higher temps and different draw speeds till you find the highest temp you are comfortable with, and you find the boundary that causes combustion (everybody should find where that line is). After that, you can adjust those factors (temp setting, grind type, draw speed, how full the bowl is and how you pack it, how long you draw for, etc) and find the perfect temp range and technique for you.
That's what's so wonderful about these more manual vaporizers. There are so many factors you can play with (which you have no control over in a much more regulated vape) to customize the experience to your personal liking.
Wanna see some real-cheap ghetto-stoner mod for a DBV? Shortly after I'd gotten mine several years ago, I made this little piece to hang off the side of mine out of a wire clothes-hanger. lol. However, it worked surprisingly well, and I still have that. (I'd love to get some sort of exotic wood piece made by one of our makers here to replace the wire thing). So yes, experiment away with whatever works!