This is my photo of both size Patrick's Spotlight blocks. There isn't much to say about making the 12.5" one this time. Increase the foundation block to 12.5" instead of 6.5", and be sure when you up-size the templates that they truly are 200%. (I discovered that not all programs increase the size in correct proportion. I have good luck with running the online templates through Adobe Photo Elements to print at 200% correctly. Straight from the internet to the printer, 200% isn't the correct size on my computer.
When up-sizing to a 12.5" block, I am having a lot of fabric waste when using a full size foundation. However, those cut out scraps are big enough to use in another project. In the 6.5" blocks, the waste seems miniscule in comparison!