I'm not really a muralist but an architecture student which happened to be on vacation and was tasked by a local church to create an interior mural. Since I have no experience of painting large walls, I have several questions which I thought the experience muralists here could give me wisdom on.

1. What is the estimated completion time for a mural sized at 11x3 meters, with complexity such as this photo (artwork by Phyllis Shafer)?
2. Since the local church has a limited budget, it's best to be wise in purchasing paint. Is it better to mix my own and create the colors as shown in the photo? (If yes, do u have a recommended line of paint brands and shades? **as far as I know, as long as I have both cool and warm primary colors and white, I can achieve almost any color**) or have them pre-mixed?

Hope someone can answer this. Thank you!!

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https://preview.redd.it/v03vpz2fzmn71.png?width=941&format=png&auto=webp&s=dde1ece0a46bba3e2e71f873ab806942509bb530