So bunch of small energy mounts, zero mediums and then a couple of large energies so that it makes low flux weapons more desirable.
This is actually the exact list of requirements for IR pulse to
NOT be good, because it gets outcompeted by HSA tac lasers, just like it does on Odyssey.
The main use case is ships like Fury/Aurora. So 1-2 mediums, no larges, and a
small amount of smalls. You tend to rely on heavy blaster for primary damage on ships like these, and IR pulses pair nicely with it, providing better flux efficiency against shields and anti-fighter coverage.
If a ship has a lot of mediums, you use one of them for anti-fighter and don't need IR pulses. If a ship has a lot of smalls, tac lasers become more efficient.