Assumption:
You have 5-10 yrs of bodybuilding experience , excellent genetics , excellent training and diet. Also using mild cycles of les then 1 gram of test with halo , winstrol , finna , eq , nova , and maybe primo and anadrol.
If this assumption is true then i belive you can be successful at the state level without GH,slin , and over 1gram of test. It's not until you reach the national level , trying to get your pro card where you see top calibre atheletes every year all trying to get the same title.
At the state level it is still unpredictable and you still have some guys who are stars and some who are off or don't have it. So if you come in there with the total package you can walk off with the title without killing yourself.
At the national level you have almost no chance to win unless your going ape shit on drugs , and even then there it is not a sure thing. Look at QuadSweep , the guy is amazing looking and took a tonne of AS and didn't crack top 15.
The conclusion is unless your willing to put your life and health on the line forget about being a successful pro bb , it won't happen.