Here’s how to set multiple In and Out points in one operation.
Open the Bin in Script View
Select the Clips you want to affect {Ctrl A selects all clips in bin}
Press G to clear any existing in/out points
Press T (sets Mark In /Out Points at beginning and end of clips)
Press Q (takes you to beginning of clips)
Use the #2 key (moves 10 frames forward) or #4 key (moves 1 frame forward) for as many frames as you want, and Mark In point
Again use the #2 key to set your desired duration and Mark Out point