From what I can see.
Quickest possible input takes 10 commands. (2,8,2,8,4,6,N,6,N,6+B+G).
You can hold last 6 and add B+G (doesn't have to be simultaneous input like EWGF in Tekken).
Seems total input time is about 40F.Any longer than this and it becomes CS.
Seems that 5F is the longest you can hold a direction. This is total for hold and release (e.g. if you pressed 2 for 6F then press 8, or press 2 for 3F, then neutral for 3F then press 8, it will not give iCS).
Doesn't seem to matter if you brush another direction, e.g. 2~3,8. Doesn't matter if you add an extra direction (was able to add 2 between last two commands).