Hi,
Just to add to the confusion:
You should be able to have the part made by investment casting with very little tuning or machining required. And no stress in the blade to cause warping. I assume you use type 316. I fooled around with a similar project for a client; applying dye to large clear areas of ortho film keeping the same colour density. I came up with a viable solution but up came budget concerns so the project was cancelled.