The 4 patch posey gives directions for a number of different size squares so will probably work. I didn't use the garden twist but set mine on point with just thin sashing. I think you're idea will be even prettier. I'de send a pic but it's still on the frame cause I can't decide how to quilt it.
Originally Posted by QuiltE
Looks like a good idea!
Keep in mind that the larger blocks, you'll lose some of your 4PP as you'll be chopping off the corners with the trellis twist piece. With the two different sizes, you could do a smaller 4PP for the small blocks ... or use the original fabric.
Another similar one is my Double Rose Trellis pattern. You can have a look at it here.
http://www.quiltingboard.com/t-122204-1.htm