The cardboard might have that shape, but why do you think it needs two bases in the back? Seems like an unnecessary expense.
Stability and better mounting points on the under side.
I wont know for sure if it needs it till i build it
If you go with two down the middle you have an 8cm wide base supporting an at least 30cm wide ship that might be a little bit too tipsy for my tastes. Its also a wedge shaped ship so if you take the two stand approach the ship will be angled down when mounted unless you prop up the front peg.
Just to be clear I'm not talking about the ffg huge ship either, this is for my own custom home project ship that I'm building.
Edited by Dodt