If you are not thinking about being an Escort (for whatever reason you see fit), why do you need the advice? Or do you not really mean what you say?
The law in the North states that a client is not supposed to pay for sex with money or in kind, so for the client there is no alternative way to have sex unless it is completely without any kind of benefit to the lady (even a meal out could be misconstrued as payment).
As someone who has never done this job, why would it even enter your head that you would need someone else to answer the phone for you? When I started up that was the last thing on my mind, I was more worried about if I would cope being with a man that I may not 'click' with or if I would be safe.
I find your line of questioning very odd indeed.
Also, why do you assume that all the ladies on this site are pretty, strong and confident? Yes of course there are some like that, but we're just regularly people in a regular job and some work at it harder than others, like every other job.
Lastly it's all in the eye of the beholder. There is someone out there for everyone and in that way, there is someone who will book you regardless of if you are short, tall, young, old, disabled or an athlete. There really are no limitations.
Now... what's the story Balamory?