I was going to let someone else spill the beans but why not let Nichol’s biggest fan (or used to be) answer the question.
EDIT: [link was removed by Admin] Jay Campbell wrote “Testosterone Cream For Your “Sack”: A Superior Testosterone Optimization Therapy Alternative To Injections?!”
150-200 mg (3-4 clicks where 1 click is 0.25 mL of 200 mg Test/mL of cream) Test via cream twice daily 
Not Debra’s fault, she’s just following orders.
EDIT: the link I shared got deleted which makes the post seem nonsensical. So here’s the photos:
Search for “jay campbell nichols cream” if you want to find the website.
From the site:
How To Properly Use Trans-Scrotal Testosterone Cream
You will want to use 200 mg/g (200 mg testosterone per gram of cream) Versa base or HRT base compounded cream.
It is extremely important to avoid using an alcohol-based cream as alcohol is harmful for scrotal skin health.
You must apply it to the base of a clean, dry and shaven scrotum (too much hair on your testes will minimize testosterone absorption).
The dosage will vary – based on your biochemically individual response and your doctor’s recommendation – but a standard dose is 1-4 “clicks” of the cream per application (~100 mg of testosterone).
Patients are typically instructed to apply the cream first thing in the morning, and again in the evening.
For myself, I have found that applying the cream once in the morning (3-4 “clicks”) is sufficient to feel optimal.