I am about to place an order for my first tumbler.  I plan on tumbling about 500 pcs at a time for my 10mm, 45 acp or 9mm. My question is would i benefit more by ordering the 2001 as there is more capacity (I'm thinking more free room for the brass to travel around the media which would yeild a better result ) or do I have it all wrong and just order the 750???? also how many pounds of media does it take to fill the 2001 vs the 750?