Hi Scarlet,
Most people on here are indie and generally speaking not so much in favour of parlours and agencies. I will say that I agree in 99% of cases indie is the best route. But I also understand what you are saying about needing to just get started, and I also know sometimes girls don't want to go indie straight away until they get a feel for the business.
So parlours, really it's not possible for us to say how busy it would be, it's impossible to know. In cities with multiple parlours it's often the case that some are busy and some aren't. The parlour itself will almost always tell you it's very busy, as they want girls to work there. Plus everyone is different anyway, some parlours cater for BBWs for example, if you aren't BBW you aren't likely to be busy in those places. Others may cater for girls under size 10, if you are over that, you aren't likely to be very busy. It's normally just a case of trial and error, work in a few and see how it goes.
The best way I can think of trying to find out is to google and look on some punting forums at reviews of the parlour/parlours in your city.
Good luck, and sorry, I know it's not overly helpful.