Roof for non-square shed

[Carrpaul19]

need some advice as to how best to fix the design of a roof for a shed with non square dimensions as follows:

left side 13ft
Right side 15ft
Front and back 15ft

The gables and all beams are level
But the final beam at the back is unlevel because of the sides being different widths. The height is also same all around. Any advice please to avoid the gutters being at a 10-15 degree and also ensure sheeting sits right on the beam

 

[noseall]

I have no clue sorry. Don't really understand the post or the shed.

Ordinarily, if a roof needs plonking on a non-square jaunty jutty building, then a flattie is the answer.