Adjusting the steering head is straightforward.
take the load off the front end.
Tighten the post nut until it is tight.
Loosen it until the front end 'drops' freely left/right
Tighten till it just binds (doesn't drop freely)
Find that perfect place where you've got freefall and any tighter binds.
Check to see that the washer under the post nut slips freely when pushed with a screwdriver
Check for any wiggle in the post by pushing and pulling on the forks. If all is set up properly and you still have wiggle, there is a problem with the bearing outer races/steering head. Once I couldn't get the wiggle to go away and discovered the lower opening of the neck was ovalized from a collision.
I'd think that about any high pressure (ep) grease would do for the bearings. Waterproof is a plus. I try to pack some into the neck tube to keep water away from the lower bearing. The plastic-looking blue is what I prefer, but I have some plastic-looking red in there right now on account of the blue was not available when I got to that point.
Remember that a bearing is really intended to go around in a circle, one way. With our swing arms and steering we have tapered roller bearings that only go a few degrees in one direction, and then a few degrees in the other. With the sideload forces present, this activity causes 'notchy' wear. If you adjust too tightly on notched races the bearing will settle into the troughs and trip over the peaks -- you'll always have some point of too loose and some point of too tight.
