The APC will make a ton of difference. I have the same combo and wont fly mine without an APC. Your RPM sounds about right. Mine will hover at a little more than half throttle but not much. Also you didn't mention the wieght of your bird.If you had to add any lead, get rid of it and move you engine on the mount to make up the diff. My engine is so far back the fuel tank hatch had to be notched to clear the intake tube.
later daveo