Cookie,
I can give you rough estimates, the problem that could arise is if you cut your fabric different than I do.
Are all three of the first cuts background, if so I calculated 1 1/2 yds. Medium 1 1/6 yds. Light would be 1/2 yd. These don't allow for any mistakes or squaring up, so I would want extra.
Hopefully someone will tell me if mine are correct, it is getting late and I am tired.
Good Luck!