We have encountered a set back. The siding on the coach is a tongue and groove board with a small V on the face to make it look like two boards. A couple years ago we installed it without any thought to paint.
We now have 4 coats of primer and two coasts of color on it. We are in bay 4 which is heated in winter so a very dry condition. We have started to see cracks in the siding.

After hours of agonizing thought and discussion we have decided to take the hit now and replace the siding. Our next step would be the addition of gold and black decoration on the siding which is going to be quite expensive both for material and labor. We know the expansion and shrinking will continue over the life of the siding.
We made a couple mistakes here. First we should have applied primer to both sides of the boards before we installed them. This would have helped to reduce the swelling and shrinking of the siding. Our second mistake was to use a white primer under a very dark final color. If we had used a dark primer the shrinking would not have exposed a white line.
So we have ordered new siding and today began removing the old.

When we apply the new siding we will be cutting the boards to length and applying primer to both sides then at least one color coat before we hang the boards. This should give us a much better paint finish because we will be doing it on a flat bench.
The material is ordered and promised for three weeks delivery. We have many other jobs to work on in the mean time so it wont be a big hit to finishing.
And in a minor improvement to historical accuracy, Harold counted the planks in the black and white photo of the original #3 and determined we should be using 4" wide planks. So we gain some accuracy.