It often comes down to knowing what you can't do, not what you can. The key to developing an appropriate training program is correctly assessing the needs of the operational environment first, then figuring out training objectives to meet those needs, then developing enabling objectives, procedures, and equipments to suit. Just because the RAF operates one way, the RN another, the USCG a third, and various other organizations in their own ways, doesn't necessarily mean any of them are incorrect.
Many of the organizations (I know the USCG does) send individuals to evaluate other programs and open their programs up for similar visits. You take what works in your environment and apply it. A heavy slathering of CRM and command trust & confidence are helpful as well.
That's how doctrine and manuals develop and evolve. There is no (and in my opinion shouldn't be) overarching goal to make all rescue organizations all over the place work in precisely the same manner. The optimum rescue procedures are a moving target and a compromise between specialization and generalization by necessity. Probably always will be.