>You're right. I'm looking for a soft interior, but when I crunch into the
>outer crust with my mouth, I don't want the roll to flatten down like a
>hotdog bun. I think it should somewhat keep its shape. I increased the
>hydration to 100% and reduced the fat and sugar to 1.125% or 1.13% but I'm
>still getting that soft feeling from these DELICIOUS rolls

A proper hard roll is made with a strong flour,mixed ,fermented and
baked properly. Increasing the hydration above 60 % is
counterproductive, you are going beyond the right standard for such
roll.
The recipe is simple somewhat like Vienna Bread with minimal sugar and
fat. These latter ingredients are added to minimize the crust thickness
that is not desirable for rolls.
Another way of doing the hard roll recipe is make it in sponge and
dough system.70/30 or 70% of flour is in the sponge and 30% in the
dough stage but I doubt if you have time for that..
Regarding yeast it makes no difference as long as the usage rate is
properly converted for a particular yeast.

One of the important requirements of a good hard roll is presence of
steam during the initial stage of baking. Convection oven due to its
drying effect needs more of it.

I have never been able to make the best hard rolls with that kind of
convection oven without steam injection....
I have used a Revent convection type oven with steam injection where
we load the entire rack and the rolls come out perfect.

Therefore in conclusiong don't be enthusiastic about hydration but keep
it in mind that shape, resliency, and crustiness is a function of
proper hydration, fermentation and baking process assuming mixing
condtions is constant.