It is my understanding that the "No what did I/should I take" threads have to do with choice of substances, rather than the dose of a specific substance. That said, I would advise downing 300mg for your first time, if you're really going to go for it.
And the 'allergy test' doesn't quite make sense to me... Unless you're trying to see if you'll have any adverse responses from it. Taking 45-60mg for an allergy test would mean a wasted trip in my book, but whatever.
Just be careful, be cool, and enjoy the ride.