Vicki - there have been a few threads concerning Rhonda's tiny blocks. I am not brave enough to personally try any of them myself but I know a lot of others have been...
I'm sure someone helpful will pop in soon... til then, I'd just click on search and see if you can pull up some hints on making miniatures.
All I do know is that you're suppose to use 1/8 for a seam allowance. That isn't much help and I only know that from looking online for the add a quarter rulers and saw that they sell an add and eighth as well for making miniatures...