I'll probably cross cut the board a little too long out here, and then let Gustav decide on the length once I get home.
He will probably also be interested in doing the painting of the sign.
Based on experience, I have found that the best way to paint such a sign is by priming and then adding a base colour. I prefer to use a spray can to avoid filling the letters with the base colour.
Once that is dry I use a small brush for painting the letters inside in a contrasting colour. I like to use red for base and white for the letters.
If I had to do the paint job on board, I would use a tooth pick for the letters. That was how I did it last time, and it is easy to get into the small corners.
The sign will eventually look better with paint since it will make it easier to see the depth of the letters.