Cutting Canopies

I have an Academy 1/72nd scale Calalina. The two blisters on the back:

1. They don't have enough panel lines
2. I want to cut the canopy open so as to show the guns there can be fired.

Has anyone cut rounded canopies? I'm assuming I need a hobby saw.

The tear-drop shaped surface is no trouble when cut vertically (at least it looks like it now )

But the horizonal part looks to be impossible because I will be cutting into the rest of the canopy.

So how do people do it?