Most of the dirt pedals I'm using have tone between 12 and 3 o'clock, but my amp is set with mids and highs fairly high, so it can get trebly, which leaves me able to better control tone with just the guitar.
I use fender amps and they are fairly bright so no, but if I am using my Fuzz I'll turn the tone knob up higher than normal do I have more control with my guitar controls, but for od and distortion I usuall keep them as neutral as I can, which usuall ends up being from 9-12 o'clock on my rigs. Witha les Paul and Marshall I can see why you might do it if you are striving for an open sound. What pedals are you using? That may have something to do with it as well...
Conversely, I run mine almost all the way down, sometimes ALL the way down, and rarely get them above 10:00
I find hitting a V1 tube gain stage harder with an OD creates alot of upper-frequency harmonics, which are cool, in moderation....basically, ODs can be quite bright, especially if using them into an amp that is already breaking up.
depends what amp I am using I get close to full up and set my amps pretty warm usually. But with some brighter amps I set the tone/treble back to reduce fizz and adjust the amps EQ accordingly.
I set my amps warm and pedals brighter because I like my cleans very round and warm and I like my fuzz and distortion to be clear and articulate but also warm and I have found this EQ setup works well for me.