Tell us what type of helicopter blade. We can then form our own opinions as to the legality/sensibility of what you are proposing.
Following on from previous responses, do you know the possible increase in load on the MRPL if you get the chordwise balance out of limits? Are you aware of the lead/lag load difference if you get the span moment out of limits?
Of course, if the maintenance manual contains the data and approval for you to do to paint, go for it.
WRL