You had the right Idea. To shorten the bass notes I put another note with a velocity of 1 where I want the previous note to stop but not on the same note. eg. if the note played is A, I will put the stop note on like Bb. I can’t remember the specifics but putting it on the same note will not cut the previous note off. I have just always done it this way and have not used or tried the new kits or features that use the note off.