I have hesitated to say this, but what the heck! What I have done in the past with a complicated piece like this is to take my steel and mark the lines I need to bend along on the backside. I then take my die grinder with a thin wheel, and I "scribe" it. As it thins the metal out along where it needs to be bent, it makes shaping the curves much easier. Then I set my welder down low and weld along the inside where the scribe is to add strength. It's probably not the best way to do it, but it's strong, makes life alot simpler for a novice, and certainly gets the job done.