I mean no disrespect but have to call Dick on his last post.

There is a big difference in cutting a pump all around in 2 places and changing the mech inside the window face. Unless you want to slather on the bondo it is a bit of work,much more than cutting a bump into the ceiling...(easier to reverse as well) Maybe I am wrong and you would just be trimming the upper and or lower edge??

At any rate it is his pump but I would only do it as a last resort.
How about a Gargoyle or other oval globe, are they not lower??