Triple lip agricultural machinery oil seals are available in a wide range
of sizes. Perhaps a little overkill?
The usual automotive oil seals are double lip.
Just fill the grooves between the lips with grease, and a thin smear on
the seal surface on the spindle - they aren't intended to run dry.
The space between the bearings inside the hub should not be filled with
grease (except for the boat trailer hubs). A $2.99 (Harbor Freight
Chinese) or $9.99 (K-D or Lisle from Auto Zone) grease packer will fill
each bearing with all the grease that is needed. Just set one grease gun
aside loaded with disc brake wheel bearing grease. Don't, of course, use
ordinary chassis grease in wheel bearings - it will melt from brake heat
on those long mountain downgrades.
My Spartan with Warner brakes has felt wheel bearing seals, probably the
original 1952 ones from their looks, and there was no sign of leakage out
into the brake drums. The felt had oil in it but not even any oil on the
face of the seal.
Al