Setting the timing on a new timing belt

I have been struggling to get the timing right when putting the new belt on.  I pulled the old belt off at TDC, but now I don't seem to be able to maintain alignment between the flywheel TDC mark and the one on the Cam sprocket.


Here are some observations:
Tiiming belt has 117 teeth at a tooth spacing of 10mm
One online source has stated that the timing belt should be removed/installed at 10 degrees before TDC

After turning the engine over 2 times, my flywheel timing lags the cam sprocket by a few teeth of cam sprocket. (Cam sprocket is aligned by flywheel requires another 2 teeth worth of Cam sprocket rotation to align within the notch.)

So the big question now is does it matter that the engine is at TDC vs TDC minus 10 degrees?