With this patch, Samus can configure her beams without pausing.

Hold Aim Down + Item Cancel to turn off Spazer, Ice, Wave, and Plasma.
Keep holding, and the D-Pad will bring them back:
Up = Spazer
Down = Ice
Left = Plasma
Right = Wave

Spazer and Plasma will toggle one another for safety reasons, but you can override that by commenting two obvious lines of code should you so desire.