Key things to look out for, for your dual-spec cat form off/main spec:
http://www.wowhead.com/?spell=46857 - Trauma may aswell render mangle pointless in PvE; maximizing energy for focusing on shred/rake instead of it.
http://www.wowhead.com/?item=40902 - Glyph of Rip decreases the amount of time you have to worry about having that finisher up and focus more on Shred/Rake.
And finally the Glyph of Mangle (Which I can't find the link to for some reason), extends the Mangle debuff time on the target by 6 seconds.