Let REW do the work

[LastButNotLeast]

Make sure graph is unsmoothed.
EQ button -> Equaliser -> FBQ2496
Target settings -> full range (assuming you don't already have bass management, otherwise select "bass limited" and a cutoff)
LF cutoff -> bottom range of speakers
click on "Set Target Level"
Filter tasks -> match range to range of frequencies you want to adjust
[edit: John suggests keeping "Max boost" to default to avoid clipping]
flatness target of 3dB is typical
click on "Match Response to Target"
Watch REW do all the hard work for you!
click on "EQ filters"
follow the rest of the directions for saving the data.

I'm seeing "only" 20 filters [the max for REW], not 100 [the max for E-APO], but the results are still fabulous.

[Larry Maes]

how do you do this for all 6 speakers at once?