In one of the illustrations I noticed a doming & dapping set where the block is made of brass. Is a brass block what I want for doming the brass washers or should I look for a block of a harder material? I also have another small question about making the domed washers. What is the purpose of doming them? I'm unsure of which direction the domed washers go in reference to the razors. I would assume the cupped side would go against the scale. Is this correct and is it for the purpose of creating somewhat of a spring tension effect for the pin?

Thanks!