Sean, if you're blocking and it keeps breaking through that means you've got high spots. Hard to say since I don't have my hands on that block, but if you're this close just use slow mechanical sand strokes.
Never was a Star Wars fan but I have to use this line.....Be One With The Body. It'll let you know hat you need to do. When I'd get to points like this my Dad used to tell me I was like a horse gettin close to home, wanted to hurry up and get there.