I want to build these 4 sided panels which have a base that does not have 90 degree corners. The base is irregular. I need a flange on each edge but, one is a 135 degree bend. The other three are 90 degree bends. What is the best way to do this? When I do this I get a really messed up corner detail in the flat. I need to do this about 40 times for this one assembly.