How to make rolls airier and crustier?

I'm working on a bread roll recipe that's 66% water (it's wet, but I'm still able to shape into rolls), 4% powdered skim milk, 1.8% ADY, 1.6% salt, 10% sugar, and 8% shortening. I divide the rolls into 30 grams per roll. I spray the buns and put in extra steam in the oven when I bake them. I also start the first couple of minutes of baking at the highest oven temperature, then drop it to about ~300F/150C for a total baking time of about 15 minutes.
It's a very basic dough recipe. When baked, the rolls come out slightly sweet, very soft, and moist. It's a decent bread roll.
However, I would like the crumb to be a bit airier and slightly drier. And I want the crust to be slightly thicker and flakier (but not as thick and flaky as a French baguette).
What adjustments can I make to my formula to achieve the crumb and crust texture that I am looking for? I'm thinking that less sugar and possibly less shortening might help? Should I drop my shortening to 3% (see: https://en.wikipedia.org/wiki/Bread#Fats_or_shortenings)? Would those changes help me?
Also, besides changing my formula, is there anything else I can do to help achieve my goals?
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How do I make my bread Crustier?
5 Tips to Bake Crustier BreadHow do you make bread soft and chewy?
To bake soft, delicious bread you need to bake it quickly at a high temperature. The bread shouldn't take longer than 40 minutes to bake. Baking for longer than this causes the crumb to dry and chewy. I recommend adding water to the oven to make steam and baking at a high temperature (230C (450F) recommended).What makes bread soft and fluffy?
Yeast ferments the sugar present in the dough into carbon dioxide. The CO2 released from the yeast fills the dough and increases its volume. Once, the bread has baked, the heat causes the bubbles to break and makes the bread light and fluffy.Crusty Bread Rolls (the best)
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