The real differents is in the measurements of the shade, bigger shade equals more coverage, and some that say air cooled aren't completely enclosed and some don't come with the glass and as for a 1000K bulb fitting in your hood, I believe that if your lamp is long enough to hold the HPS bulb you shouldn't have any problems, the only thing I would take care to check is if the socket on the 1000k ballast kit has 4 screw holes or 2 because your hood may have a 2 holed socket holder where you may have to drill holes to make another ssocket fitt properly.
Others may have more experience, so maybe get some more opinions.
Adieu