I tried Armor Smith when I was building my Death Trooper, and it was really difficult to get right. I think the creator has kind of ghosted - From what I understand it hasn't been supported in a couple years.
For the scout, I went with 110% somewhat arbitrarily. I cut out slices vertically and horizontally to check the fit of the shoulders, biceps, and forearms, and I think that 110% seems to work. So far I have only printed one half of the chest armor, with the second half underway as I type!
I'll keep y'all posted!