I have not built one but I can only assume the generous dihedral was to help with stability at the time this was designed. It being a 'low' wing, I wouldn't remove to much but there should be no issue in removing 1\2" on each wing. Also consider removing a bay on each wing. Will increase roll response. Looking at some pics it doesn't look to be 1.5 on each side but that big wing can be deceiving.