GG's

I recently bought Bob Flexner's book, "Understanding Wood Finishing".  He
mentions that saturating a piece of wood with oil, for example, by soaking
one end in linseed oil until capillary action causes complete penetration,
will stabilize the wood from shrinkage and swelling from water-vapor
exchange.  Michael Dunbar's book says that he places old, checked planes in
linseed oil, and that as the oil is absorbed, the checks may close.

My questions are:
1. Were the 19th century woodies generally finished by placing in linseed oil
until they were saturated, or were they finished on the surface only?

2.  I have seen old planes that look like they have compression shrinkage
(something else I learned about from Flexner's book).  Would a wooden plane
be more apt to get compression shrinkage if it had oil on the surface only or
if it was saturated with oil?

3.  Which oil is best for saturation, boiled or raw linseed oil?

4.  If i make a new wooden plane, what finish will best preserve it?  Would I
be better off with a wiping varnish or some other finish other than straight
oil?

Thanks much in advance for any replies.

David Sobel