careful on the weight....
like albert said...Pancaking, the worse part is it will smush it down so there is no surface to expose, once you get your pad a little dirty, wont be able to clean it out much.
also bog, depending on your machine...
id rather have a little faster and a little less weight...
Diamonds are like 10-15lbs per stone, maybe a little higher...but with 9 diamonds (3 on each of the 3 drivers on a cimex) they want over 100lbs....
here is my set up for doing stone or concrete