First what brand of engine do you have? 30 sized engines vary considerably in power output. Also, what does your plane weigh?

I have (2) DLE 30 engines that seem at their best with something like a Xoar 19-6 through 19-8. In general for maximum climb performance you'll want to stay with a fairly high diameter prop with reduced pitch. For speed, reduce diameter and increase pitch. I run the 19-6 on a 15 pound CUB and it has almost unlimited vertical climb. The 19-8 is on an 11 pound YAK and it has unlimited vertical. I rarely use a tach on these engines so I have no idea what RPM they are turning.