Use the same midhorn, tweeter and crossover as the seven π cornerhorn but scale the bass bin larger, like the version for the JBL 2241, but tune it for 22Hz using a 4" long, 4" diameter port

Some more questions to further clarify, if I may;
In your testing and listening experience, would you consider the Delta Pro 15A model to be a performance compromise over the Omega Pro 15? (Purely budgetary motivated question, I can interpret the specs well enough).
Regarding the larger cabs you suggested for the Delta 15- Presently I have 37" high bass bins- and they're TALL. Higher cabinets than this would put the mid/high drivers above seated ear level. With respect to the null axis, is this a problem? I presume the Omega Pro would also produce lower response in the bigger cabinet without changing the crossover- true?