“its too late for ‘impounding’ ballot boxes to do any good”
Correct.
“they’ve all almost certainly been stuffed FULL with thousands of brand new ... ballots”
Correct.
“the only thing that can be done now is to disqualify all of the ballots from these couple of counties”
Correct.
Actually, there is a process where the fraud could be rooted out. There has to be a card or book that the voter signs prior to getting a ballot. I would be willing to bet there aren’t sufficient cards/signatures to cover the overvote. They probably either added a vote for Nelson on an undervote or they added addition ballots.
If they added additional ballots, the card/book totals won’t match, it they just penciled in a vote for Nelson on an undervote, a sampling of voters in a precinct will expose the fraud. I’m betting because of the ballot design, they added votes for Nelson on undervotes. Phone calls to voters in that preceinct will expose the fraud.