Brook 12A Datasheet

I ordered the original photo fact off of ebay as I had never seen all the data. Since I am building it this year I should have it. My version will be larger due to parts selection. The first build will be pretty much stock. I am curious about what tweaks would you guys make to the 12a? Not wanting to get too far from original design.

 Original schematic with error of C3 being reversed. Any other errors?