My hood sits flush in the back and also in the front but in the middle, on the sides it sits about 1/4" high. I have seen many others like this. What can be done to make it set better?

This is the hood getting a little bent from years of closing the hood after the hood hinges tighten up from corrosion and not being lubricated. Happens on many vehicles. Possibly a good body man can work some magic to get it back to wear it should be.

Chinese hood? Can’t tell if it’s a flat hood or 400 hood

I had the same thing on mine. As long as you're flush in the back to the cowl piece and the front, here's what you can do. Get a short piece of 2x4 maybe 5" long and put it in front between the radiator support and hood to support it. If your hood is already painted, protect it with a towel. Now get on top and walk ONLY on the outer edge of the hood, ONLY on the center section where it stands up. I would recommend measuring the highest point before. Mine was .250". Walk on it for a min. get off and re-measure..repeat. I got mine to within .05". Good luck.