Here are diagrams for some keyboard layouts I could make for you. Note that the standard model can only have the basic 30 keys, whereas the advanced model comes with 31 keys as standard (the drone is the 31st button) and can have up to 38 buttons on a G/D or up to 40 buttons on a C/G
Historically there were many ideas of what the “extra” buttons on a 38 or 40 button concertina should be tuned to. The layouts I have included showing 38 and 40 key instruments are just some of the more common of those historic layouts. If you would like me to make anything different do get in touch and I can advise if it is possible.
CG Jeffries layout anglo 31 buttons
CG wheatstone layout 31 buttons
GD jeffries layout anglo 31 keys
GD wheatstone layout anglo 31 keys