If you have been good since the beginning of July, you should have a little over a centimeter of good hair at the scalp end . It takes a week or two for consumption to show in the hair. May and June will be approx 2cm at 1-3cm from the scalp.
This is not an exact science. Hair grows at different rates. But, if your hair is quite short, you need to protect the bottom - i.e. do not drink! You would also benefit from growing out and chopping off growth from May and June. It might make sense to do this with a few trims rather than one big cut taking off several centimeters.
Tests are by consent, you cannot be forced. However, refusal to test can justify the court in drawing their own conclusions. I suggest you offer to pay and insist that you have charge of test arrangement if testing is going to be ordered. If the accuser's legal team has control of instruction there will be dirty tricks. This happened to me, I had to overrule the order and take charge of arrangements myself. Testing was not in my ex's interests. Her side wanted all to be decided on mud-slinging.
PEth test period timing is more exact. You could do one now and one every 30 days from now. In 60 days you would have three months of the higher standard test. Industries that require sobriety use PEth over hair strand.
