Here's my graph paper scribbles. I started with a diagonal point layout I drew for something else and expanded it.
There are many ways to describe diagonal sets, I usually use A and B designations. A are the first ones you put down point to point. B are the ones that fill in.
The thick pencil lines (ignore the inner ink lines) show the current size. Each of your blocks will add about 10" for each one that you add to your A rows, but don't forget to add you B blocks. The circles show the blocks that were originally half blocks that are now full blocks.
For the size you want and what you already have, you might consider setting with alternate blocks, you still might have to make a couple.
edit: Forgot to add this link, last year I made an on-point quilt with sashing. The blocks were 7.5" unfinished. Here's a picture and some more about that project if you want to try sashing. I started writing up a tutorial on how to figure out the yardage needed for on-point settings but I sort of abandoned it. Still, I have the start and some good info an will go back to it if it will help.
2019 Fabric Moratorium