This late in the season looking in from the outside you don't worry about getting your 4th line on an even role. You can easily doubleshift a guy like Ray, Larks, DBC, Compher, Copp, Ras etc.
Sprong is a difference maker on the PP. Without him that 2nd unit is just a time killer. You can play him on the PP and exlcusive ozone starts if needed and even or down.
Defensive zone put in any of the guys above. This is leave is on the floor season. If your top line players need to hit 25 min and Seider pulls in 28 so be it.
Especially in road games where its a lot harder to get the matchup you want.