Your question is somewhat difficult to answer without knowing the characteristics of the tubes involved. If you can achieve AC and DC balance with a quad on each side, this would be preferable. However, if AC balance cannot be achieved, you should try splitting the quads with two on each side to see if AC balance can be achieved that way. There may be a slight imbalance between tubes on one side, but it should not be so great as to cause a problem.
How will AC balance determined? Some people apply a sine wave and adjust for a DC null on the output, others insist on a distortion analyzer.