Somewhere a few years ago I read a discussion on plating head lamp buckets. I can't remember where it was. Any hints?
Don't know which particular discussion you were remembering.
Silver and aluminum, un-oxidized, both reflect very well.
If I recall correctly, untarnished (un-oxidized) silver is just about the best reflector material you can have. The problem is that it oxidizes rapidly so needs frequent cleaning/polishing. Which removes material. So eventually you will be down to the brass base metal of the reflector and you need to get it replated.
Aluminum also oxidizes but there is a company that can put a glass coating on top so that all it ever needs is a non-abrasive cleaning so it should last a long, long time. I has this done to my headlights in the 1980s and the reflectors are still good.
What ever you do, don't plate them with nickel or chrome: They don't reflect light as well as silver or aluminum.
http://www.ply33.com/Repair/lights