First of all, I am not an instructor and merely a young bloke with a fresh CPL, no IR or ME. But I would like to give a slightly different perspective on this. The major difference between a private pilot and a commercial pilot is not whether you are able to perform a perfectly coordinated steep turn or not. A private pilot with 7-800 hours in a SEP would probably perform better than a fresh CPL-pilot with 150 hours (like me).
In my opinion, it's the attitude towards flying that makes the big difference whether you suit as a commercial pilot or not. If you always think
safe and make the right desicions the examiner wouldn't care if you loose 100 ft during a steep turn or mess up the wing rockings. He might give you a remark on these elements but I would be extremely surprised if he failed you just because of that.
The superior pilot is the one who uses his superior judgement to avoid situations which might require superior skills.... I guess you've heard that.
What I mean by thinking safe is that you do a proper pre-flight inspection, think about
why you check each item not just do it. Always do careful mass & balance, operational flight plans, fuel calculations and weather studies. Sometimes it feels overkill, but one day it might save your life. By doing all this boring stuff you minimize the risk of anything bad that can happen and the risk that still exists, is so small that you are willing to take it.
For the handling bit, the CPL syllabus do require more precision than the PPL. But from my experience the examiners are not extremely fastidious. Co-ordination exercises like steep turns, chandelles and lazy eights I find really helpful. You have to use your feet and timing is important when doing lazy eights and chandelles especially. Simulated engine failures in flight is something I do on regular basis and power off landings as well. If there is something the examiner look at, it's how you cope with an emergency situation.
My 2 cents
(or 50 öre whichever is less)