One of the things I don't like - the instructions never give you a "trim size" for the intermediate pieces. it will say to take a 3.5" square and cut it diagonal twice, and then to make HST with them, but does not tell you want the UF size of those HST should be.
I have a chart that shows what the UF size is based on number of rows in a 6" block.
2 rows, UF 3 1/2"
3 rows, UF 2 1/2'
4 rows, UF 2"
5 rows, UF 1 3/4"
6 rows UF 1 1/2"
7 rows UF 1 3/8"
8 rows UF 1 1/4"
Most of them with templates, I measured with the UF size would be so I could do the same thing.