I will try and cut the stab and level it out. And check for warp.
WHOA! Slow down! This is why I suggested you start another thread -- I'm going to give some direction, and then this thread is going to get totally sidetracked in "how to unbend a bent airplane".
You don't need to cut the stab out unless it is either hopelessly warped or hopelessly tilted.
"Hopelessly" meaning that you've tried straightening it using heat, and definitely failed.
I've straightened tilted stabs on profiles where one tip was as much as 1/4" higher than the other, by getting the fuselage good and warm ("warm" is like hot, only the 'coat or paint isn't melting yet -- "I can still hold it without yelling" isn't warm enough), then twisting it in the opposite direction about as much as the original twist, then holding it there until everything cools down. It takes a long time, because you want the heat to penetrate into the wood, and if you've fiberglassed the fuselage you want whatever resin you used in the 'glass to soften a bit. So you need to warm it up
slowly, get it
good and warm (really, the hotter the better, unless things are melting off the plane, turning brown, bubbling, or catching on fire).
It can be done.
I'd try that
first, because it's much less invasive (unless you scorch the paint -- big bubbly brown marks counts as "invasive"). If you just can't get it to work (which has also happened to me),
then take Mr. Berry's advise and cut & wedge. (And, if you cut & wedge and miss by a hair, you can probably bring it the rest of the way with heat).
Note that sometimes they'll settle back in the direction of the warp or tilt -- just keep at it. Usually if I can get it to move at all, repeated treatments will eventually see it settling down where I want it to be.
Ditto any warp in the tail feathers. For it to work you probably need the heat to extend into the wood, and if the wood is cupped then you'll probably have a fight on your hands -- I'd aim for the left and right tips to be level with the stab root, and just close my eyes to any cupping of the wood unless I wanted to rip the stab off and build a new one.