half a tooth on a 44 tooth would yield about 4 degrees. seems like a small slot. hondaman and mreick, could the 550 be advanced that much with stock settings?
The 4 degree setting (forward) would move the torque peak forward (toward lower RPM) about 1000 RPM. Moving it back 4 degrees will make it come in later, about by the same 1000 RPM (actually a little less, more like 800 RPM, because of other factors). Moving it forward makes the bike seem stronger all the time, because the torque is more available to you in normal driving ranges. The peak power, though, will be a little less at higher RPM unless the pipes are also changed to an effective scavenging design: this is true in both situations, forward and back.
To improve horsepower at higher RPM after moving the cam forward, while still keeping the newfound lower-end torque, try richening the main jet by about 10% and then drop the needles 1 notch in the carbs. If the "notch", or power drop between the lower torque peak and the higher HP peak becomes objectionable, modify the spark advancer by either using lighter springs or by reducing the total advance, but then add the difference as static (idle) advance. This will brighten up the midrange, but might end up requiring higher octane fuel.
To modify the advancer for less total advance, bend in the tabs that stop the weights at full advance. Try to do it equally on both sides; it can be done with a small ballpeen hammer and an anvil. When you put it back into the bike, run RPM to 3000 and see where it stops: it should be early. Then advance the points plate until it reaches full advance at 3000 RPM: at idle the advance will be more than normal. An overall change of 5 degrees should be your maximum.