I probably wouldn't worry too much about upgrading the ironworks gear. Once you hit around 55ish the quest gear is going to exceed it. I don't think there is any real ratio of gear to character level. Most people that are at 60 are going to be above ilvl 180. Depending on what your end game goals are really depends on how much grinding you want to do for the max ilvl gear, as of now its 210. The level 60 dungeons give out 160 gear.