[One Winged Angel]

I'm gonna give you a hot tip: it doesn't matter, play what's most comfortable for you. Players at the top level for this game use vastly different scroll speeds. There are other factors which help influence what speed works best for you.

Fwiw I use 2.1-2.3, which are pretty slow scroll speeds, but I look directly at the receptors when I'm playing. There are other players around my skill level that use speedmods above 3, who likely look much lower than I do. It's really just personal preference, your scroll speed isn't a limiting factor to how well you can play unless you're using something that isn't working for you personally.