mashing with corn

[JonB]

We are gonna try mashing corn again sometime soon. I've read the various posts on this site and I seem to understand the process. However it is not clear to me what form of corn to start with. Advice/clarification is most welcome.

-Clearly flaked maize is the the best, but this is expensive
- Corn meal could work, but the stuff I see in the store appears to be enriched with iron and niacin. I don't think I want that stuff in my mash. I also read about the corn germ being oily and again I don't think I want this in my mash either.
- Cracked corn may not be available to me, but I do have a malt grinder. Can I get untreated popcorn kernels and grind these? Again what about the germ?
- Up north we don't have grits, so this seems to be out. :-( We also don't have animal feed stores here and so its the local supermarket that I need to work with. Time is also a factor, and so I need to balance this as well.

Finally, I do have some left over flaked maize (about 2 lbs) that I'd like to use. If I'm mashing the corn bits or meal, should I put this into the pot at the start (with a touch of malt for the enzyme) or later on?

Thanks to all in advanced and for making this such a useful resource.