Hope I don't sound like a nag on my suggestion for this and hundreds of other jobs, but there is a two word answer here: Bandsaw.
Gentlemen, a vertical bandsaw will allow you to cut this shape entirely, accurately and quickly. This whole job can be easily accomplished in one hour including the layout, the cutting and the sanding. Once again, our bandsaw has been used several times per week, every week for 32 years. Delta 14" Vertical Bandsaws are featured on fleabay all the time. Usually they go for around 400 to 600 dollars. I saw one recently for 450 in great condition which is exactly half of what we paid 32 years ago! With 3 speeds, you can cut wood or steel.
Just a suggestion,
Tracy