There is no perfect way to do a quality check short of visiting the site to see for yourself.
What Gladstone does is fine but it's not perfect. Just gotta take it with a grain of salt.
You can't plug in micro climates and drainage factors, altitude or anything else. It's just an across the board analysis of all parameters based on on other stations.
I commend him for trying because as we know there are people out there who don't take pride in trying to achieve the best data possible. A long as you know you're accurate, that's all that matters.