Correcting for multiple positions isn't difficult.
One simple way to do it is to average all your readings from various listening positions. The more the better. Just depends on how nuts you are.
Use Excel not graph paper. You have a computer for crying out loud use it.
Compute the averages based off all your listening tests. The more you take the more you will converge to the mean of the listening area. Then apply your corrections to the mean.
FYI you can use both a DCX and AS together. In fact it might not be a bad idea to do so.
A DCX isn't required for a Kappa build as long as you use a 20hz high pass filter such as the fmod. You will still probably outperform whatever sub you are currently using. However it is best for integrating the subs. I'm not aware of an AS that can configure 2 subs. The High Pass Filter is a must.
DCX's are very versatile and can do much more than EQ. So if you still want to EQ with AS then by all means do so. Just use the DCX as a crossover and sub integrator.