"causing just minor delay on most pages, and slightly longer delay on pages where you're actually submitting that many values."

so what you are saying is having it at 1,000,000 is overkill and the servers ram will allocate that much everytime even though i don't need it, so i really need to experiment and if 500,000 helps, it will reduce load? (even though that load will really will be minimal?). basically try to trim it get the optimal perfomance from the zc site?