Mary I wasn't able to respond to your question until now...I finally found the right mix (for me, and I do think it is a personal thing) one has to find a balance between quick draining and retaining enough moisture that you don't have to water every day in the summer! And this is different for each of our microclimates.
I use 40% topsoil, 35% pumice and 25% chicken grit (size #1) I mix the heck out of this so it is well mixed! I use a top dressing of the chicken grit - this seems to work great! The top dressing keeps weeds down, and keeps the semps little new roots able to move through it yet drains very fast!
Hope that helps! Can't wait to see the photos