Nozzle geometry

Is there any specification on extruder nozzle geometry for different version, drawings etc.?
I have a MK8 0,35mm nozzle, but after purchasing a few I find very different versions around.
The flat part on output around nozzle exit seems to vary a lot, mine is app 0,8, but i assume it may have big influence on how large you can set your extrusion width.
In my case i would not think anything larger than 0,8 would be successfull, but if you had one with a larger flat area maybe?
Any experience with this parameter and how it may influence printing quality?

Edited 4 time(s). Last edit at 05/13/2014 11:48AM by justcurious.

There's some at [reprap.org] or [hydraraptor.blogspot.com]

Too big and it catches on stuff, too small and you can't constrain wider traces.

Edited to add: [forums.reprap.org]

I saw that folks thought wider nozzles could potentially help smooth top surfaces with good calibration, but they tended to degrade bridging.

Edited 1 time(s). Last edit at 05/14/2014 10:07AM by DaveX.

Thankyou DaveX
I did not find answers on your links, but I will keep looking for some info to enlighten this issue.