separate

I am going to grow with a 600 mh hps combo light with a dimmable ballast ( 600,400,250 ) in the kit both bulbs are 600 watts, do you need separate bulbs to run on 250 or400 or are the bulbs dimmable, would appreciate some help please. Thanks in advance Trev

After harvest, do u have to hang the whole plant upside down to dry or can you cut the branches and hang them separately? Thanks ahead for any info!!