Bearing up grade rear pinion gear

Hi
Is there any reason why I can't fit two of the larger 6004 (12mm) wide bearings to the rear pinion drive gear on my D as opposed to one fat and one thin (8mm) if I fit the two larger ones it will give me around a 15mm spacer for the oil seal (10mm wide)to sit in.
Thanks for any help
Is there any reason why I can't fit two of the larger 6004 (12mm) wide bearings to the rear pinion drive gear on my D as opposed to one fat and one thin (8mm) if I fit the two larger ones it will give me around a 15mm spacer for the oil seal (10mm wide)to sit in.
Thanks for any help