I use 98% warm wax method and have used it for 37 years. Odd occasions like today I have done a mobile so I take my small microwaveable pot of brow wax with me. It cools in a jiffy so no spillage on the way back home. No strips needed either. Less for " mrs forgetful " to forget, lol.
I did train with both types of wax so I am confident with both. I would not consider changing permanently to hot wax now as it has given me a steady income and my clients are very happy. My speed is very good., so you will benefit from a little extra hands on training i am sure.
Percentage of waxing is difficult to work out, but if you do every client that walks through your door a brow wax at least , then that will give a good idea of earning potential. Is that what you mean ?
Hope you find a suitable course
Best of luck