You will pickup a fair amount of bitter with a 20 and a 15 minute addition and with 15 minutes of boil you won't get much aroma of the Mosaic.
I'd be inclined to stick to 1 oz Chinook for 60, 2 oz Cascade at 2 min and save the Mosaic for whirlpool (170 degrees) for 10 after flameout, or...