To my knowledge, SRS is effectively the de-facto communication method, apart from Discord and text chat. Concerning etiquette when trying to fly in coordination with others, in my experience it has been very spontaneous. In every case I will usually use text to ask a specific pilot or group of pilots what their objective is, and how I could help. On some servers, especially the Hoggit servers Human Ground Control Intercept/AWACS are pretty easy to coordinate with using SRS, usually it goes like this: “[AWACS Callsign] this is [Your Callsign] [Your Airframe] loaded for CAP, ready for tasking.”. AWACS will usually respond and task you how they see fit based on your load out, be it CAS,CAP, SEAD etc.