Okay, this is not going to be easy.
The small waveguide of the Seas-DXT controls the sound radiation only at high frequencies. In the manufacturer's measurements (quasi half-space measurements) you can see that the waveguide controls the radiation well down to about 5kHz (constant directivity CD behavior when comparing on-axis and 60° measurement).
View attachment 112953
By "removing" the baffle from the tweeter as early as possible, it radiates wider than with a baffle (which acts like a simple waveguide).
Simulated Seas-DXT in cabinet v9 without XO (10° steps):
View attachment 112958
This allows us to significantly expand the CD behavior of the waveguide in conjunction with the baffle. The 60° frequency response (FR) now runs more or less parallel to the on-axis FR down to about 1.5-2kHz.
This can be better seen by looking at the graph normalized to the on-axis FR.
Simulated Seas-DXT in cabinet v9 without XO (10° steps) normalized to deg0:
View attachment 112960
The situation is somewhat different with the woofer. There, the cone acts as a waveguide at higher frequencies.
What we want here, however, is that the transition from the 2pi behavior (the baffle influences the radiation) to the 4pi behavior (the wavelength is so large that the baffle has no influence on the radiation) starts as late as possible and the transition takes place as evenly as possible.
Therefore, (in very simplified terms) the woofer should have as much baffle around it as possible. Because the baffle also acts here like a simple waveguide focuses the radiation at low frequencies.
View attachment 112965