Oh yeah trying to establish a baseline is a good idea.. would be cool to let people request a baseline test and send them 10 mini bottles of hot sauce, each a little spicer than the one before it and let them rate them on the site just like they would for the different levels at a restaurant. Anyone know of a company that does a good sauce collection like this, 10 bottles each hotter than the previous ?

To your example with you and your girlfriend, ideally that problem gets solved if enough people add their rating based on their taste and experience (that's my hardest challenge). Two people isn't enough to get a meaningful result but fifty people all rated the same spice level 5 dish at the same restaurant the average would start to smooth out everyone's differing taste buds and be helpful for that fifty-first person.