Automatic Cross-dissolve - custom duration

I watched several tutorials, including this one:
https://youtu.be/LTGr5AB0ZC8?t=4
on how to add transitions to multiple clips.
How would I give my automatic transition a custom duration. I find 2 seconds to be a little too long.
I like them to be barely noticeable.
Where do I change the length in such way that it becomes standard for all auto-generated transitions?

I wish transitions could be applied using the Adjustment Layer, so all clips beneath the Adjustment Layer would share a common transition.

Thank you.