How to edit on "track" above main storyline efficiently?

Hi, me again. Here's what I'm trying to do efficiently. I have b-roll stacked above VO, which is above music. I'm using Connect to Primary Storyline shortcut to drop b-roll footage down above the VO. So far, so good. No, let's say I added 1 second too much of that b-roll clip, so I go back 1 second, do a mark in, go to the next clip, hit the Connect to Primary Storyline key again, hoping it will drop the clip down on that same level. But, of course, it doesn't, it goes above that last clip. So, what I have to do is, when I go back that 1 second on the first clip, do an Add Edit, remove the 1 second portion, then do the next edit. This is pretty cumbersome. What am I missing?

You can shorten a clip by positioning the playhead to the point you want it to end and while its selected or the playhead 'ball' is on it press option-] (left bracket)

Or, which might be even more what you want, you select your connected clip, press command-g to make it a secondary storyline, then position your playhead at the point you want the new clip to start, select the secondary storyline (NOT the clip within it) and press D. This overrides the clip in the secondary and adds the new clip in the secondary storyline to what ever length it has. The trick is to select the secondary storyline itself on the top grey bar. Doing this allows you to use all normal edit function like insert (W), override (D), append (E) on the secondary storyline the same as you do on the primary storyline.

Story line... advanced ... wow... I never use I just have 15 stacks high of clips and then compound clip them down when they look ok