You said;

<I wonder if the traction-rich folks could tell us traction-impaired ones
exactly which tires they're using, and if they use different tires in
the summer.>

On my '87 GL I've used Kelly Metrics, Pirrelli P-4000's, and Pep Boy's best
all in a 205/70 - 14 size and used them year round.
The only snow that has stopped it was the 'Blizzard' of '96.
We had 18 inches of snow with drifts above 2 ft.
She just don't go too well when she starts pushing snow with the front bumper!

Sam Bateman
'87 Vanagon GL