Good morning Jillaine, I'm sure you had a restless night over this one.
This board is an excellent example of good minds coming together.
MTS has the right idea, Because there is such a large discrepency in the sizes, go the muslin template way.
Size up each triangle, add a strip to the sides that is needed to bring it to the correct size, and MTS is also correct in making the strips a little longer to be trimmed later.
Starch the heck out of it, let it dry and then do the next one.