First off. We charged 35 dollars a half hour at our lesson/training barn, IF they paid for 6 lessons up front, they got price break down to 25 dollars, but money came first.
When I did them I got 20 for 1/2 hour lesson.
Any less and you are biting yourself in foot.
And curious about the ducking under neck? Since when did this become a no no? Done it all my life, as do all the horsepeople I know, of various breeds/disciplines. It is not unsafe, any more than anything else working around horses. Simply have to let horse know you are there.
But your insurance carrier may not be gung ho over this, and you need to check with them.
Secondly, if you don't know what you are doing, and I mean as in many years with this, an accident could have lawyer grilling you "So what exactly is your background in training riders? Where did you study? How many hours in your degree were necessary for you to be able to teach horseback riding."
Of course, nothing may happen. If you decide to go ahead with this, you need to establish right from get go that student has to be attired properly, and behave. Parents can stay first lesson, after that, they can't hang around, as I have had parents cluck to horse, or wave arms around inside pen while hanging on it. One time of that was all it took to start that policy.
I also had sheets of homework, word search for horse words, conformation drawings showing parts of horse, book lists for them to read, that sort of thing.
Horses make me a better person.