The horn path in the 4520 is 8ft, not 12ft as can be read in JBL's literature. The 4530 is 7ft.
8ft is 2.40meter meaning the 4520 will load down to 35Hz (1/4 wave) and will be "generous" at 70Hz (1/2 wave fundamental) with a dip (phase inversion) at 105Hz
If OP had a digital crossover, I would have suggested ditching the 2404 and keeping a simple two-way system with CD compensation on the 2360. But crossing at 300Hz may be enthusiastic. I would stick to 350/400Hz. At the most.