Yeah, this doesn't look great. Different systems have different requirements. The 4-5X should be considered the minimum you need to be overlap the tallest spot.
Flying higher would help.
Since you are at the minimum allowable height you would want to up to the overlap a bit to make sure you can resolve the roof properly.
Mapping a slightly larger area would help.
Orienting your passes along the long axis or the short axis would likely help to. Doing it diagonal cuts into the overlap you get pretty severely when doing such a small area.