We had an overnight permit for 2 hikers on the Mt Whitney main trail last year for Oct 18/19. We needed an extra permit for another hiker, so we showed up at the Eastern Sierra Visitor Center on Oct 17.
About ~10-15 mins before the walk-in lottery, a rep from the USFS will announce the daily morning lottery (I think it was at 10am). He/she will then ask one person from each party to step forward to pick a number out of a tin can (and also politely ask for 'no double dipping').
As it turned out for us, we were the only party waiting for a permit, so it was a single person lottery. We were issued an additional permit for our third hiker (for free). The USFS rep said that there were only a few extra overnight permits available, which came as a surprise to him mid-Oct.
The numbers on that list show many more, so I'm thinking that they did not include no-shows in the permits that they were issuing for the walk-in lottery. The number of overnight hikers encountered on the trail was more consistent with that list (not many on the trail... not even close to 60).
I made 3 trips to the Whitney Zone last year and the people at the visitor center were always very helpful. They will offer up alternative hikes and even offer a permit for more nights than you originally requested.
They also rent bear canisters for $2.50/day and have a drop-off location at the center.
