Well first of all, we are a harm reduction forum, so we aren't here to tell you what a good dose is to get as high as possible, but what a safe starting dose would be. You can always take more if it's not enough but you can't undo it if you take too much. Secondly, there are a lot of threads already on the subject of starting doses for methadone if you look for them.
And third, methadone affects different people very differently, so it's impossible to give you a dose that would be safe for you yet still get you the desired high. Just start out with 10mg and wait at least 3-4 hours before even considering whether or not you should take more. Also it's not going to feel like oxycodone.
And, there is no such thing as a Percocet 30, do you just mean a 30 mg IR oxycodone?
