[RMcNeal]

I got the Lock-n-lube fitting specifically for mine. I was having trouble getting grease in on several and this fitting locks onto the zerk so I can apply more force without it coming off. The end with the zerk fitting doesn't turn if memory serves. It has splines to align the bolt at 3 or 9 o'clock so the hole in the bolt faces sideways and not up and down. The nut on the back side should turn and tighten and draw the other side tight.
I use the Mobil 1 Synthetic grease on bearings and the wet bolts. It's on the Dexter recommended list for the bearings. I think any NLGI-1 rated grease will work. The zerk fittings are a standard size, nothing special.