For my setup, I'm using my laptop along with a Tascam-US 122 mkII and a Dayton EMM-6 microphone. I took everything outside to a pool area that overlooks a field and a small lake, which should have been plenty of room to properly measure. I set the speaker atop a ladder and got to work.
First I got everything set up with the correct levels in REW, and made sure not to change any of the input or output settings on the Tascam, or the volume on the amp until I was done testing everything.
For the measurements, first I took a measurement of just the SEOS/DNA360, then just the 2512, then both in parallel. This is a set of measurements was taken without moving the speaker, the microphone, or changing any settings, and is used to set up the acoustic offset of the drivers as described here: https://www.box.com/shared/ouxjjsx0m8bs00cil5iq
Next, I took measurements of the waveguide and the woofer individually, and directly on axis for each one. I also measured each driver about 22 degrees off axis horizontally to simulate toe in, as per bwaslo's recommendation.
Here are the measurements for the acoustic offset:
These are the measurements from the tweeter level:
And these are the measurement from the woofer level:
The next step, and what I'm currently working on, is designing the crossover network by using this data in Passive Crossover Designer.