With my above tests, I came to a couple of conclusions: 
I way prefer the Dark Driving in high gain, it does what it says on the tin....dark drive . 
With the Beta & BB, I think they work best in low gain 
The Demon, for me, shines in high gain. 
 
It should also be mentioned, that they all gain a certain something when put through a loud cab in a big room.....not stuck direct into Logic  
 
I had a Darkglass B7K, found it a bit too fizzy for my liking. Sounded too 'Fizz blended with Bass' as opposed to Bass drive/distortion. Having said that, people get some great results from them, just wasn't for me. 
 
Si