I am also curious as to whether ETG levels reduce hourly similar to alcohol content?

You are going to find out when the lab results come in.

We aren't going to offer ANY advice on ways to help cheat on a future random test.

Metabolism is unique to individuals and MANY factors are involved but don't think hourly rates for alcohol levels to decrease, think HOURS, as in 8 or more. A reading of 500 ng/ml is NOT good given the accepted standard of EtG tests range is 60/80 hours and does indicate more than casual incidental use and a cause for failure.

That you drank 64 hours ago is meaningless, without knowing the time range and alcohol content to measure against other factors, as a glass of wine may be okay, but a gallon of gin is definitely NOT.

Thanks for the input. I am not looking for ways to cheat or pass the next one. No more drinking. I will let you all know the results.