I would suspect the knife setting of about 1/64" above the cutter head
is correct. This is basically the setting for my Powermatic 8"
jointer, as well. Probably a similar setting for all such jointers
(and planers) with similar heads. The recommended setting of the
blade, top-dead-center, above the outfeed table, for my Powermatic, is
what Doug mentions, .002". I would suppose this is applicable for
your Delta.... and other similar jointers. If you can set yours less
than that and be okay, great.
I have a (newish) Delta 15" planer, but haven't had reason to change
blades, yet, so not sure what that knife/head setting is. Eye-balling
it, looks to be a good bit more than 1/64". My brother has a 12"
Powermatic planer and, if I recall, that knife/head setting is a tad
more than 1/64", also.
As for as I know/understand, 1) the knife relative to the head setting
has nothing to do with nor is dependent upon 2) the setting of the
outfeed table relative to the knife/head unit. Those 2 settings are
independent of one another.