Masteron is a great drug for getting a hard, grainy appearance. You'll want to use it with some prop. In the last 4-6 wks of the cycle, winstrol would help to dry you out even further. All of this is assuming that you do the work to get lean enough that the muscle isn't covered by fat. 

As for your question about GH, yes, it is possible to get lean enough to compete without GH. Many people do it. Gh will get you leaner though and help you maintain more lean mass while using it in a diet. In lower level competitions, GH is less important. As you progress from smaller novice shows to bigger NQ's, more guys will be using GH and by the time you get to the jr national level shows, more will be using higher doses. The better your genetics are, the less you will need to depend on drugs in general. If you only want to compete for fun, just do the best you can and have a good time doing it. I had competed without GH in NQ's and did just fine.