cam timing

[bgmayes]

so i know that if you advance cam timing on any engine it will increase your power at lower rpms but hurt you at higher rpms. and vice versa retarding cam timing will give you better power at higher rpms but hurt you at lower rpms. this is why the I-vtec is amazing you can advance and retart cam angle at any rpm range. now without putting vehicle on dyno and actually seeing where each angle has most effect in rpm ranges is there a given point in rpm range on our engines that we want to stop advancing cam timing and start bringing her back down(retarding)???
also should you have you timing in sequence with your cam timing i.e. advanced cam = more advanced ingnition timing then when retarding cam timing start retarding your ignition timing as well??? any words of wisdom?