If you see my post on the states of an application the following are very important
R10 - usually 45 days - Meds are all happening simultaneously.
Eligibility - Status within 60 days - final results depends on where the LVO is.
GCMS help you in ensuring that your have things on track, but is a personal choice to order them or not. I recommend keeping a tab from R10. so 45 days is good about time. Some forum members suggest 30 days, but that is too early.
Then every 30 days to see when the eligibility is recommended passed and finally passed.
This is my suggestions, but you can see the trends in your month and request GCMS accordingly.