Hydroton pebble size??

I have to wash some new hydroton.
Does it make sense to put larger balls on the bottom of the net cup and put the smaller balls on the top.
Thinking that the larger balls will leave more room for the roots to get around. The smaller balls on top will help lock light out to the roots better?

Yes the smaller ones in my experience are easier to work with on top, and as you mention they are better at keeping light abay from the roots...