Hi Diob,
First of all, the new coat of arms should be simple so that we can embroider it without many problems.
Until now, the colors used in our current coat of arms are the colors of the north (green, white, black) + gold. Most of us wear clothing of those colors so something similar would be prefered, but we are open to new colors if it is pretty 
The style of the artwork is up to you! You should consider the sewability so a totally complex drawing with color gradients would be impractical.
We also made a list of important points in Paolos Trutz so you can get a feeling for the city:
- Capital of the Northern Realm
- Lots of Aeris related Stuff since we are the captial of the Aeris Seal
- Current Coat of Arms contains: Coat of arms of the North, two griffins, the symbol of Aeris
- Has the Citadell of Magica
- Has a really big colloseum
- Has a lot of bath houses
- Has a Military Academy
- Has a big district of poor people
- There are many embassies and diplomates of different countries
- There are many officials of the Northern Seal
- Has a big Park of the Elements and a botanical Garden
- contains the palace hill and the palace under the dominion of the Nyame
- Is next to a river and has a harbor in its suburb
- Next to the city there is a seal pyramide, where only the top is visible
Hopefully this can answer your questions
If you have any more do not hesitate to ask!
