Would be very handy to know which bike you are wrenching before you ask for advice.
However, keep in mind that widening a port increases the ability to get more material into the cylinder (or allow more to leak out if you go to far or mismatch the sizes). This will generally give more to torque than RPM. Changing the height of the posts will increase that ports event timing (or allow the event the port is responsible for to short circuit the other events if you go to far or mismatch the timing events).
If you have issues with setting ignition timing I would strongly suggest you seek a mentor-student sort of interaction with someone who wrenches what ever bike you are riding BEFORE grabbing the dremel.