I haven't been a member here for too long so my voice of reason may not be respected as those who have been on this forum for ages.
Seeing different MPAs will allow you to figure out what each girl likes/dislikes. Although they are sex workers and are putting up a front 100% of the time, you'll find out very soon which girls you click with and ones which you don't. Girls that click with you will enjoy the domination aspect of the demands that you make.
Seeing as though Jennifer has rave reviews from multiple members of the forum, I think you should go with what those have seen her have said: take it step by step, let her take the lead and you guide her in terms of what you like. You can definitely be pushy right when you walk into the door and tell them to suck your dick, but understand that although they're sex workers, they are people too, and people have feelings and emotions. Don't think that because you're paying for a service, you're entitled to be a certain service level. I guess you can look at it akin to: walking into a retail store and demanding something from an employee, vs. asking for something from an employee; you're going to get shitty service until you leave the store if you go the former route, and that employee will be talking shit about you to their fellow coworkers.