Just wondering if it'd be a good idea to climb up a couple branches before taking a shot on a hog? If so, how high up would be reasonable to avoid any angry pigs?

WHY? Can u shoot sittn n balanceing on a branch? Could you find a branch suitable to sit on with hogs nearby to shoot? If you are worried about getting up a tree before shooting a hog, then you need to think about hunting them a bit more. I have killed hundreds of hogs and have yet to worry about it. Thats part of the thrill of the hunt. Just learn to shoot straight and accurate and you have nothing to worry about.
And yes, I have been charged several times. Both by shot hogs and 2 times by hogs that were not shot, YET!!!!! Shortly corrected thereafter!!!!!!!!

when they charge, ya just need to pull your feet off the ground...if its 600 lbs, i'd just dump the clip in em. i saw a 400 lb hog shot twice in the , head, a lung shot and a shoulder shot still tryin to kill us....and some just drop..shot placement is everything...
you certainly dont wanna become a piņata

I'm not really worried too much about poor shot placement, I'll just be hunting with a single shot and I'd like to know what's a good height to climb if i have the opportunity. I'll be using a red dot, so target acquisition won't be difficult, I just won't be able to reload very fast.

You just don't get it. There is no hand guide on what the correct height is to avoid being de-manned or legged by a PO'd hog!!!! How high can u jump when chased by a wounded or PO'd hog? And again, are you going to have a suitable branch to jump onto where you have hogs around to shoot?
Why don't you just learn to spine or brain shoot a hog before you endure on your endeaver if you are so worried about it. That or just don't do it!!!!
That or just hunt from an elevated stand and you won't have to worry about it till you have to get down and then I guess you will be worried of you can out run a hog!!!!!

I'm not going to say it's a bad idea, but I've never even thought about it. I don't think I've ever even had the opportunity to go up a tree before shooting at a hog. At least half or more of mine have shot in open pastures, and the rest I've stalked until I got close enough to make a shot. Climbing a tree would certainly create too much commotion and scare the hogs away. Now, if you're setting up an ambush at a water hole or feeder, maybe it's a consideration. However, in my (limited) experience once I shoot, the hogs take off like greased pinballs on fire in whatever direction they think safety lies. So far I haven't been in their direct path. If I were, I think another shot would convince them that their safest path lay elsewhere.
I almost always carry a pistol with me (to finish off a wounded hog) but I doubt that I could get it out fast enough to defend myself should the need arise. With a single-shot weapon, maybe just make sure you know where the nearest tree is so you can jump behind it.

The biggest hog I have ever shot without dogs was sitting in an Oak Tree branch in Lake Wales, FL., in 1964........