Pretty good but he use's the word chemical in the instructions and I'm not sure that is a good choice of words.
"The amount of each chemical"
Personally, I try to minimize the amount of chemicals added to my DIY
And while Nicotine is technically a chemical most call it a Nic base and PG & VG are components.... then the balance are flavors.
With the scrutiny
vaping is under we don't want anyone to think we are adding unnecessary chemical.
Just a thought.