[strat61caster]

Ok, you're back into grad school, nobody wants to hire someone who would go through all that trouble.

I just used a drill press, ruler, and a scale rated to a few hundred or ideally thousand pounds, but you do you. Race teams will get into how each spring acts dynamically but the rest of us can't afford a sample size to actually do anything about it (other than put the slightly stiffer spring on the heavier side of the car), maybe something useful there for measuring lifespan of a spring (I'd presume elasticity degrades over time but who knows) but the deltas are probably too small on quality springs to be measured with amateurs equipment.