After doing some forum searching, I am seeing mixed "C" rating reports on the 20ah polymer cells. Some as high as 30C.
If anyone locates a discharge graph on these cells, please post it. Or at least post a link to it.
In the meantime, a better solution to tab soldering? Tab Clamps! I kinda like the idea. This gives the user the ability to take the pack apart, should the need arise. Also, high discharge capability, provided the design is right.