Honestly, I just don't draw the line down the center of the lighter fabric. I'd rather draw my sewing lines. It seems to work better for me because I can eyeball the cut line. And yes, I do get 2 HSTs.
I have done them by cutting the squares the recommended 7/8" larger than the finished block size but found that it left me with NO leeway in sewing, pressing or cutting. I had to be soooo careful. When I overcut the block size to 1" minimum, I don't have to be so darn perfect.
Here is another method - I have not tried it but Rhonda swears by it:
http://www.quiltingboard.com/t-46365-1.htm
Here is one method where you get 4 at a whack BUT I don't use it because of where the bias (stretchy) edges end:
http://www.quiltingboard.com/t-74134-1.htm