If you think this amount is good enough for you and the Manager/trainer, then I’m sure it’s the right salary. You could also offer as incentive a % of the sales or training or memberships he/she will be selling each month. You can set up a scale which will help you and the manager/trainer refer to in order to figure out his/her monthly income.
Keep in mind that having one person doing both duties (manager and trainer) it could be hard in keeping up with both duties. A manager has a number of responsibilities that are different form those of a trainer and if you want to grow and run your business flawless, you will need to separate the two. The last thing you need is to have an employee who is overwhelmed and eventually burn out.
I’d have to say that what Harris says is what I thought whenI saw your question. If a person is training and managing, and if they are getting bonus pay based on hours of training it kind of sets up a situation where they may feel economic pressure to put more effort into the training. What I have seen over the years is that an adequately compensated carefully chosen manager is one of the things that can really help a business do well. Sometimes it is the owner who does the hands on management, and hires someone to manage the training, and sometimes vice versa, but if you split it in two you can hire people who will do well for you what they do best.
Regarding the pay…. well, it is good if you are able to pay on the higher end of what the going rate is in your area, but I am sure you have researched that well.
Good luck, I am sure you are excited about your new venture.