Front - large
Center - large (unless it is smaller than the right and left front - then small)
sub - none
surrounds - none
backs - none
If all three fronts are identical then you can leave the balance alone. If the center is different then you will need to adjust the level of the center in the speaker set up menu so that when the noise comes out of each speaker the volume is the same at your chair. The delay or distance setting will be almost the same but it is good to adjust this too, Check the manual on how.