[strat61caster]

Speaking very generally, does a stiffer spring reduce the amount of camber required for optimum tire usage?

I would imagine that with a stiffer spring (or wheel rate if preferred to account for sway bar changes) you will get less suspension travel on the wheel meaning that your dynamic camber changes are lessened translating to a reduced amount of static camber to get the ideal contact patch under load during a corner.

Maybe that's true but the sensitivity isn't there, i.e. going from a 130 lb/in spring to a 260 lb/in or 620 lb/in spring only changes the required camber by a couple hundredths, not several tenths of a degree (of course driven by how heavy the vehicle is, 130 to 260 on a 1,500 lb car vs. a 3,000 lb car will be magnitudes different in it's effect).