I have sanded one of the halves of the top; the squeeze out cleans up very easily without softening or gumming up the sander.
As far as finishing goes, I have been thinking about Watelox Original as suggested in numerous posts on walnut tops here on LJ. Mineral oil/beeswax mixture is not an option for sure. Waterlox is durable and forms moisture-, stain- and heat-resistant film; scratches can be repaired easily by applying locally a new layer of the finish. Walnut is an extremely porous wood. It’s ring-porous; that is, visible pores are concentrated in the early part of annual rings. Sealing the surface of the counter top is therefore a must.
As a test and following suggestions found here on LJ, (left to right) General Finishes Salad Bowl Finish, Minwax Golden Oak stain, and Minwax Special Walnut stain have been applied to a scrap block. The stains look the same, the Golden Oak being of a bit warmer color at certain angles. GF SB Finish looks lighter than the stains. Most probably, I will stain the counter top and then apply layers of Waterlox. Hard to decide on the stain at this point with no Waterlox applied.
I expect to get some natural seasonal movement from walnut. High porosity in a kitchen environment will for sure increase this movement. One of the issues with Waterlox and other film-forming finishes is that this seasonal wood movement may crack the film. A top made of 6” face-sawn boards will for sure show some movement, don’t know, though, what to expect here, will see how it works.
Walnut is a porous wood, but not as bad as red oak though. You can actually see through 1” of red oak looking at the end grain, this is how porous its earlywood is. A lamp is behind a 1” thick cross-section cut piece of red oak:
-- "If you're not counting the ripples when throwing pebbles in the water, you're wasting your time."