If you use a 1" wide putty knife, you can "skim" the paste wax, effectively building a thin layer of wax on the knife. Spread the wax from the knife on to the buffer pad like you would butter a piece of bread.
Treat the wax like it's a really hard block of butter and the buffer pad is a warm, soft piece of bread. If you try to cram a piece of butter on to the bread, you'll tear it, but if you "skim" it on, you're usually going to be ok.