Hi Cathy -
First - FINISHED means AFTER it's sewn into the quilt.
The block BEFORE it's sewn into the quilt is referred to as UNFINISHED.
Really, really, really important distinction.
I don't use EB rulers (as I prefer to draft my own sizes), but if it says 4x8 FINISHED, then it started out as 4.5"x8.5" UNFINISHED block. Unless, of course, EB has her own terminology. Which isn't very helpful.
The problem with rulers like that, though, is that people then never really understand the math behind it, and then can't make their own custom sized FG unless there is a ruler for it.
That's why I prefer to do my own.
Traditionally FG blocks are twice as wide as high. So you see a lot of 2"x4" and 3"x6" FG (all sizes are FINISHED).
The creates one proportional image, and the math for figuring out the starting size of the pieces is much more straightforward.
But there is nothing wrong with making a 4"x 6" IF that's the design and look you want.
Or a 1.5"x8" FG block.
Take a look a Caryl Bryer Fallerts quilts - she's got every imaginable size - and I seriously doubt that any of them are "standard."
http://www.bryerpatch.com/images/qui...ompliments.htm
The math for the construction of the sky pieces - and the assembly is just a tad different because you'd be dealing with a rectangle, not a square. But that's a whole other thread.
But if your own pattern calls for a 3.5" x 7" FINISHED FG, then you'd cut a rectangle 4"x7.5" and two 4" squares for the sky background.
There are multiple ways to piece a FG block - rotary cutting the pieces, templates, rulers (like EB), and/or foundation piecing (usually great for accuracy if you have a stream of FG).
Depending on the project, you might use one or all of the above methods.