The prospects for CPL instructors should soon be very good with the more experienced chaps being taken on by the airlines. There is no specified minimum number of hours to be able to instruct for the CPL. However I would always look for an instructor with at least 500 hours of reasonable ab-initio experience and preferably one I'd trained myself - you also have to have had the resriction lifted. Rates of pay will vary from school to school but IRRenewal is about right I think. The more basic qualifications you have (I/R ME-FI) the better placed you will be to earn a good income, but you can add these as you progress through the system. Choose a good FTO to begin with and you should do well.
Good Luck