Balance control

BOSOZ:

I would like a balance control. However my skills in electronics are poor, and I'm not sure if I can manage to implement this circuit at output p4 without risk of higher output impedance:
http://sound.westhost.com/project01.htm
...so I though off using an alternative (my Bosoz is unbalanced only):

1. Use my two-channel attenuator 5K @P4 as master volume.
2. Use two one-channel 10K pots @P1 as input gain, thus being able to adjust balance.

The reason for this is that I prefer only one master volume control (P4).

Please comment.