Armor as Damage Reduction?
 

I recall this was an option in Unearthed Arcana, which I know is minimally supported for the Pathfinder rule set here. Is there any way to make that an option? Thx.

There is an official alternate ruleset for this in Ultimate Combat. AFAIK, the rules for it are fully implemented in HLC, so if you have that book for Hero Lab and the ruleset is activate it should work.

But I haven't tested it...