If you Google "Bonnie Hunter Cathedral Stars class list" you can find information on how much yardage per color or color set.
That is probably the easiest estimate. I learned to calculate yardage based upon block size and number of units using the Harriet Hargrave Quilters Academy Volume 1 - she does a great job laying out how to compute the number of strip sets you will need for each type of cut - which in turn leads you to the computation of yardage needed.
This is a lovely pattern, but I'm not sure I would start a new quilter off with lots of complex triangles and blocks.
Cheers, K