You can't get a one sentence answer to that question.
Well, unless you can find a cheap older version of Electric Quilt (v5 would be great for this).
You first need to understand how a block is made, and how to determine the basic grid pattern of each block
(((a 9patch has a 3x3 layout, a sawtooth star has a 4x4 layout, a pinwheel has a 2x2 layout)))
before you can begin thinking about resizing a block correctly.
How are you going to make the blocks? Hand piece, machine piece? Paper piece? Any applique blocks?
It's certainly doable (and actually sounds like a great fun project) but it would help to first have all 63 blocks separated by grid type and/or sewing method. That way you can tackle a pile at a time instead of facing 63 blocks and wanting to scream.
Will the colors be the same as the actual blocks on the barn, or are you going to come up with your own color story?
Also, maybe something can be done with the layout of the quilt to make all the different sizes easier to deal with.
Do you have a pictures of all the blocks in one place where I could look at them?