You have to take a minute and set-up what you want to have print for the Client copy, otherwise you are getting a ton of worksheets etc. The Filing copy is limited. I also send informational pages to the clients if I think they would appreciate it or should have it, comparisons, depreciation schedules etc.

As far as cost, I use Flat Rate Priority Mail at USPS.com regardless of the weight. It may cost a little more, occasionally, but it gives me some peace of mind with tracking and delivery confirmation at a fixed cost.