I dont mail anything anywhere, never have, never had a problem.   

The brokerages give the IRS all the individual sales records, I dont see why we would need to send them as well, IRS already has it.

I make sure my gross proceeds match the 1099B to avoid any CP2000 notices and separate my summary lines into st covered, lt covered, st non covered, etc. so they land on the right page of the 8949