Last year*, I debuted park factors split based on the batters' handedness. I left those alone for the past large number of months, but recently began adapting some of my algorithms to work with Retrosheet data, which you might have already noticed. It's been my hope to eventually start putting old Mariner teams into context. For instance, does the 2011 Mariners have the best pitching staff in franchise history? I'm almost sure of it, but to actually be sure, I need fair comparisons and for that, I need park, defense and league adjustments. The defense is coming as previously mentioned and here now are the park factors.
*Pause: awww, Cliffy!
I haven't yet decided on what year range to go with. When I address specific players, I may just calculate the factors for the years involved. The ones listed above, sans batted ball types, cover the entire life of the Kingdome from 1977 through to 1999. The batted ball (GB, FB, LD, IF, HR) start in 1988 since that is the earliest year that data becomes useful. There's not much difference between the two sides, but I would not have expected there to be given how mostly symmetrical the Kingdome was and the enclosed nature of the dome prevented any of the atmospheric effects that especially plague right-handed hitters in Safeco Field.