I remember seeing coastaltool.com or something similar, but it has a plastic backing plate, where the one from CMA has a rubber one (i have no clue what i'm talking about)...
The 7336 is got the #6 weight in the machine you want. The 7424 comes with the # 5 but if you get the 7424 from coast tool they sell the # 6 weight. Your cheapest way is what southern boy said thats what I did so you don't have to mess with the weights and shipping cost.