OB 3-way with Beyma

A friend is contemplating the next project. Size is a factor so leaning towards 12" bass drivers in U-shaped OB.
Initial thoughts:

- Bass: 2 x 12" (Beyma 12BR70 8\Ohms in parallel)
- Mid-high: Beyma 8CX20 (or 8CX300Nd if funds permit), or
- Mid-high variant #2: FaitalPro 8HX150 (or 8HX200, ditto)

The crossing between the bass and mid/high section will be active.

Any opinions and/or suggestions to the above? A pair of 12BR70 looks (on paper) like it may work well in OB even though the Qts is a little below 0,40 but DSP (DEQ) should help there if needed.
Or it is safer to go with a single 15" even though that will increase the size and will deviate from the initial idea of narrow-ish baffle (Eminence Delta LFA 15, etc)?

Any experience with the above listed 8" coaxials?

All remarks/comments are welcome at this early stage of planning.
Thanks to all in advance.