ok,
without otter for a start,
your line from windscreen to cowling ring is a straight line, it should change angle at the start of the breech cover and travel steeper, also there should be a very slight hump to this section due to the to humps either side being just visable .
next, the cowl ring needs dropping on the top edge from the centre to the finish.
after checking both your drawings otters and yours, they are both wrong on the cowl ring, but otter got the change at the breech cover but both missed the very slight curve.
red lines show where i mean.
images to back up my observations



