I'm not sure if you are asking about a built-in to pool spa or a stand alone type...
my primary hot tub is a stand alone kind & it has two seats with neck jets...

all of my seats are actually at different heights, but I haven't measured distances to the floor well; sorry...

if you'd like to read my review ( & get more info) on this hot tub ( or reviews on other types & brands)
check out epinions.com

My review is for a beachcomber 578:
http://www.epinions.com/content_244051185284