I have an idea:
How about, you can only craft the hull blocks? As in, it will be color grey. However, when building, there will be an option to add color to the blocks your placing. For example, you have 1 hull block. You want it to be color blue. So, there will be an menu that will enable you which color the placed blocks will be. This will require paint. Say, you have blue paint in the inventory. When you place the hull block, it consumes both the hull block and the paint. What will be placed is blue hull. What if I take it off? Well, I think that it will make much more sense that the block you will get when you remove is not the hull and paint, but the painted version of the block.
tl;dr
when placing a colored block, it consumes the paint and the hull block.
when removing the block, you get the colored version instead of paint and hull.
How about, you can only craft the hull blocks? As in, it will be color grey. However, when building, there will be an option to add color to the blocks your placing. For example, you have 1 hull block. You want it to be color blue. So, there will be an menu that will enable you which color the placed blocks will be. This will require paint. Say, you have blue paint in the inventory. When you place the hull block, it consumes both the hull block and the paint. What will be placed is blue hull. What if I take it off? Well, I think that it will make much more sense that the block you will get when you remove is not the hull and paint, but the painted version of the block.
tl;dr
when placing a colored block, it consumes the paint and the hull block.
when removing the block, you get the colored version instead of paint and hull.