I like the Pinwheel/Iris formation on Vassal, but I haven’t had the same luck IRL. Trying to turn a ship into the formation is also a challenge, but I’ve found that doing a barrel roll into a formation is much easier. If any piece slides during the early moves you could bump and lose your action during that first exchange, which is terrible.
I seem to think one of the guys from Omaha (Aaron maybe?) used it in a store championship winning list. I’m guessing he’s either super precise in his movements, or gave it a bit more room using barrel rolls, etc.
For tight formations I tend to prefer the staggered second row, which is in the same grain as the iris. Just over half a base between each ship in each row, and the second row can be pretty tight behind the first if you want. With four ships it forms a sort of diamond.
But more typically, I run formations corner to corner with a bit of space. It helps me not run into my own ships when blocked.