Making the balance pipes between side tank and bunker. There is very little room up against the drop flange where it rivets to the side steps so make sure those rivets are flush on the inside otherwise the flange of the balance pipe may well foul and also make it impossible to get the fixing nuts on. The nut under the bends is impossible to get on I found so its only a 7 point fixing. Should be OK.
To make the balance pipes I chose to machine them from solid and put a lid on top. Fortunately I built a small CNC mill that enables me to do that. When I say "solid" I actual silver soldered 3/4" x 3/8" bar together to get the very rough shape. Also made the walls 1/16" thick and the top (lid) from 1/32" brass to make it stiffer and easier to solder.
To get the balance pipe in place it will just maneouvre in the gap between the steps and the bracket holding the steps to the frame.