the block is designed to rest on the tank flange. This gives it more support to keep from bending or breaking.
Yes, you will need longer bolts. The bolts on your machine are 25mm long, you will need 50mm long bolts. If there is enough demand, I *could* supply bolts, but would rather not. I am not trying to make a lot of money here, but I need to cover my costs.
Just added these notes to the original post.