Make sure you take wattage into account here. You may get the right total resistance, but the wattage requirements for each may be different. Being in the tweeter this probably won’t be a huge deal, but still.
Also, honestly, you are MUCH better off doing room treatment or using a DSP than attempting to do this in the crossover. Changing a tweeter crossover resistor is never going to give you the fine grained control over your balance problems that you need.
Consider equalizing by using wall mounted diffusors on one side and stand alone diffussors on the other. Alternatly, put the speakers in a corner instead of flat against the wall.