Look if you are offering advice make it totally unambiguous. You made a
comment on what the original poster stated to what the blockwork would be.
I think that was very dangerous as the original poster may follow your
advice. I and most of the others have started for a wall 10' high use a
structural engineer. I see no difficulty in following that advice. You may
have structural engineering capabilities, (but I personally doubt it) if so
how can you advise on what is required, in possibly, a very dangerous
situation, without knowing the full facts. Your advice about a good
foundation and good drainage behind the wall is fine but to say use "x"
block for the bottom third then use "Y" block for the rest is not good
advice in this situation.