Ok here is a follow up on my research...
A french guy tested 164 servos thoroughly and made a windows application. Unfortunately it's in french. However he also tested the TowerPro SG90.
The program can be found here:http://www.teaser.fr/~osegouin/aeromode/servos.phtml
Click the link saying: "Téléchargez le programme et la base de donnée V2.2 de Mai 2007" at the bottom of the page to download the program (if you're interested).
Here is a screendump of the program showing the data for the TowerPro SG90:
With my limited knowledge of servos and poor french I have deducted that the SG90 will draw max. 700 mA at 5V and 835mA at 6V.
However it also seems that the general performance of the servos increase a lot when running 6V?! Didn't know that either..learning a lot these days
I looked up some of the words I didn't understand:
Couple = torque
Vitesse = speed
But I could not figure out what this means: "Tps de positionement (moy)"?!
However it has to do with speed/positioning and the performance running 6V is almost double than when running 5V (78% vs. 42%). Perhaps something I should consider too?!
Anyway I'll end up running 5/6V and 12A (or something).
So know I wanna ask:
1) Is that at lot of current for a PCB (even with extra fat lines as Ran suggested earlier)?
2) How will the Arduino board react to 12A (perhaps 6V) when I connect the two grounds?
3) Could it damage the servos (if for example only one servos is connected will it be "overfed")?
4) Other posible problems due to this setup?
5) Should I choose 5V or 6V...pros and cons?
6) Any good shopping suggestions for 5-6V 12A adapters (tried to look for a surplus one like Ran said but couldn't find anything suitable)?