[Mister Moose]

Grease: Does not pour or flow at ambient temperatures.
Oil: Flows in all ambient temperatures.

I think this is the bulk of what Brent is saying, with the added proviso of shear strength. And shear strength really doesn't matter much if there is no replenishment.

Having heard about Penrite, and not wanting to disassemble the steering box YET AGAIN for oil leaks, I ordered a pint of Penrite.

It does not behave like a grease. It flows. It is somewhere between thick catsup and thick molasses. It's quite slippery. I don't know how well it will flow into the oil channel in the sector bushing, but it likely will over weeks as opposed to minutes. This is all that's needed really. And even quicker into the needle bearing that has more and wider spaces. If you assemble with grease first, I think that could obstruct any oil from entering the bushing grooves. And grease can dry and harden over time, another reason not to use grease in places where you can't force the old grease out under pressure with fresh grease.

I installed it. I needed to rig a threaded funnel into the steering box and let it flow in over several days* before it was full - in the fall in ambient temps of 50 degrees or so.

I agree this would be entirely unsuitable for a high speed gearbox.

* Because my funnel was small (about an ounce) and I would check on it just a few times a day. Bigger funnels would allow much faster fill if you're in a hurry, but don't be in much of a hurry.