Bicycle Mechanics - Alum frame with Alum seatpost - any old grease work?

Replacing seatpost and I noted that the stock seatpost was installed with white grease (white lithium?). Is there any prefered grease to use vs common auto grease. I know that normal auto grease can dry out and cake up over time so I would prefer to use a grease that would not tend to do that in my seat tube. Sheldon's web site does not note any preference for type of grease. Since this is used to avoid a seatpost from seizing in the seat tube, I would assume that a lighter grease would be prefered over a heavy grease like used to pack auto wheel bearings. I would think that a heavy grease might tend to dry out and make it harder to remove the seatpost later.

Anyone have any reason to recommend one type over another?

Replacing seatpost and I noted that the stock seatpost was installed with white grease (white lithium?). Is there any prefered grease to use vs common auto grease. I know that normal auto grease can dry out and cake up over time so I would prefer to use a grease that would not tend to do that in my seat tube. Sheldon's web site does not note any preference for type of grease. Since this is used to avoid a seatpost from seizing in the seat tube, I would assume that a lighter grease would be prefered over a heavy grease like used to pack auto wheel bearings. I would think that a heavy grease might tend to dry out and make it harder to remove the seatpost later.

Anyone have any reason to recommend one type over another?

I just use Phil Wood or Park bearing grease. If the grease is going to dry out it will take years so I wouldn't worry about it too much.

Use whatever grease you have available as they will all work. Despite greasing it, remove, clean and regrease the seatpost at least once a year.