rounding over the edge of the teardrop

So I'm ready to put a rounded edge on our hatch, and will later do the teardrop. Seems like a silly question, but I've not found the answer anywhere else:
Which way should I hold the router? My intuition is to put the plate against the side and have the bearing run along the roof, but I can't find any examples online where folks have done it this way. Seems like it will take some strength (or at least stamina) and concentration to keep the plate flat against the wall.
The alternative, of course, is to put the plate against the roof and bearing against the wall, but when the roof curves, it would be difficult to keep the bit perpendicular to the surface.
So I'm thinking the first solution is the correct one. I've also figured out I have to go from right to left, as the cutting will be done with the underside of the bit.
My intention is to use a 3/8" radius round over bit, and to make several passes, "lowering" the bit about 1/8" each time.
Comments? Safety concerns?
Thanks!
Tom
Which way should I hold the router? My intuition is to put the plate against the side and have the bearing run along the roof, but I can't find any examples online where folks have done it this way. Seems like it will take some strength (or at least stamina) and concentration to keep the plate flat against the wall.
The alternative, of course, is to put the plate against the roof and bearing against the wall, but when the roof curves, it would be difficult to keep the bit perpendicular to the surface.
So I'm thinking the first solution is the correct one. I've also figured out I have to go from right to left, as the cutting will be done with the underside of the bit.
My intention is to use a 3/8" radius round over bit, and to make several passes, "lowering" the bit about 1/8" each time.
Comments? Safety concerns?
Thanks!
Tom