I've found that if your board is customised using the Easy Customisation only
and not using CSS, you can actually export the EC block to another board.
(1) Go to the Admin Center >> Easy Customisation of the board you wish to copy from
(2) At the bottom of the page you will see a button which says "Create EC Block" - click on this and a new window will open.
(3) Select all the text in the little box and copy it to your Windows clipboard (CTRL + C).
(4) Go to the Admin Center >> Easy Customisation of the board you wish to copy to
(5) Paste the stuff you copied into the little box on the bottom right just above where it says "Parse Block" (CTRL + V) and press the parse button.
(6) All the new colors etc will now be on the page. If it looks OK, then you can press "Submit" - it won't work unless you do that.
Have a bit of a play with this on a test board - NOT a real board!
(You can copy
from a real board of course.)