How do you get yeast rolls to the fluffy consistency of the Hawaiian sweet rolls from King Hawaiian

And when you add the butter, be sure it is at room temperature, not melted. Add it as you would for brioche dough, dotting it in slowly and allowing each addition to be fully incorporated before adding the next. This allows the butter to be incorporated via the emulsifying lipids (fats) in the egg yolks. If you melt the butter, you liberate its water (18% of its weight/volume), which makes it available to the gluten in the flour, running the risk of overdeveloping, and therefore toughening it.

I think this might be what you are seeking,
http://www.yammiesnoshery.com/2013/02/hawaiian-sweet-rolls-fluffiest-rolls.html

I find that a really wet (almost more of a very thick batter)and sweet dough usually produces a bread with that fluffy consistence. And a little bit of fat too.