Source Four vs S4 jr.

You can pretty easily calculate your beam size and brightness by looking at the photometrics tables. Take a Look at https://www.etcconnect.com/WorkArea/DownloadAsset.aspx?id=10737461834
or
https://www.etcconnect.com/WorkArea/DownloadAsset.aspx?id=10737461933
15m is approximately 50 feet. Remember that your true throw distance is the hypoteneuse on the triangle made from horizontal distance from the stage to the light and the vertical distance from the actors face to the light. From geometry A^2+b^2=C^2. If your light are 50' horizontally from the stage and 30' in the air then the True throw distance is C^2= 50^2+30^2 or TTD= 58'or 18m.
At that true throw distance a 19deg will make a beam 19.5'w by 41' deep.
Depending on how big you want the areas and how bright you might want to go with a 14deg or 19deg or maybe even some 10 degs.
HTH

You can pretty easily calculate your beam size and brightness by looking at the photometrics tables. Take a Look at https://www.etcconnect.com/WorkArea/DownloadAsset.aspx?id=10737461834
or
https://www.etcconnect.com/WorkArea/DownloadAsset.aspx?id=10737461933
15m is approximately 50 feet. Remember that your true throw distance is the hypoteneuse on the triangle made from horizontal distance from the stage to the light and the vertical distance from the actors face to the light. From geometry A^2+b^2=C^2. If your light are 50' horizontally from the stage and 30' in the air then the True throw distance is C^2= 50^2+30^2 or TTD= 58'or 18m.
At that true throw distance a 19deg will make a beam 19.5'w by 41' deep.
Depending on how big you want the areas and how bright you might want to go with a 14deg or 19deg or maybe even some 10 degs.
HTH