You will get a lot of opinions on this subject. One thing I will tell you is if you follow the service manual you will have a mess when the grease expands and starts coming out.
I don't grease mine. In the summer that drips all over my garage floor and I'm tired of cleaning it up. Their greased when the bike is assembled which should last and really how much movement occurs in that area? It's mostly at very low speed. I mean there not wheel bearings. If they start to make a grinding sound I'll change them. But if want to lube yours any general purpose grease should work, it ain't the space shuttle.
I've been using HD's grease. I don't care for the low drop temperature (especially in Florida) but I'll deal with it. If you haven't thought of it already, you'll save tons of time if you replace the stock zerk fitting with a 45 deg fitting. Otherwise you have to remove the entire nacelle (a.k.a headlamp bucket) to get to it.
Use what's in the grease gun, and wipe the bottom of the steering every so often to keep from getting this drip that people are talking about. Never have seen mine drip and it get's greased when it is supposed to.
i went with a 45 degree zirk fitting and used a high temp white lithium grease,,it made a mess but i just wiped it up and havent had any dripping, it being a high temp grease,,,,and i know at least there is grease in there !
i problably wont be greasing it again for a real long time,,,,,