This pattern was tested for colour blind accessibility by https://www.color-blindness.com/coblis-color-blindness-si... It will also still make sense when printed in the black/white setting on your printer.

Yardage as in the sample: 3625 yards
350 yards each of four colours
Background: 2225 yards

Size: Finished blanket will be approximately 8 times bigger than your 7-round square. Sample measures: 62” square