Thanks. All valid reasons. But I don't team dive, I dive independently with a buddy. I will watch my buddy to see if he has any problems, but unless he needs my help with something unusual, he can do everything for himself, the same as I can. I check my own gas before and after the switch, even though we're only carrying two stages and it's left/lean right/rich so we always go to the left for the first switch
Why not use one upline each? It's easier for the boat to see us, we both have a reference for stops, and I have something to clip my stage to when I swap gas. As for communication with the surface, that's just a matter of what they're expecting to see. If they expect to see two balloons & only one balloon pops, there's a problem. We both carry two SMBs, if we need gas or someone to come down or whatever, I write a note and send it up with my spare SMB. We practice this with the boat from time to time, getting them to drop down a spare stage for example
I think the point is that you should have a system, a method of doing things, that is consistent within your group of divers. We have one, you have one; I don't see any need for mine to be the same as yours any more than I want you to change yours, Having said that, if I learn of a good process, I'll discuss with with my buddy & if we think it's worthwhile we'll trial it
I don't appreciate some smartass "just sayin" that I should change the way I do things without giving any reasons why and calling me a bad diver because I don't watch my buddy stow his stage reg hose or hold his reel for him while he does it