Bill- You have asked the magic question that has puzzled many people about the Bahtinov mask.
If you want to focus using the first order then you need to optimize your cuts for f2 for the hyperstar. However the third order can be used to focus.
Here is a photo of a Mag 3 star with a C11 F10 taken with a DSLR camera. This mask is optimized for F4, but you see the third order still is very effective for focus.