My first attempt at this sort of block was Sarah Nephew"s book....which was wonderful....and I still consider the quilt I made, of hollow cubes, with what seemed to be an internal light, my masterpiece. Now owned by my son and his wife who display it in their living room.
I did not starch....just cut per the directions, was careful with bias edges, and had no problem.
If I knew how to post pics, I would....lol.
My advice is....don't be afraid.....it's not as difficult as it looks and the results are stunning. I did a merge of dark to light blocks, from the bottom up.....
Don't agonize...just do it one step at a time.