I am almost finished with my first build (in fact, I am hoping to wrap it up tomorrow), but I am hung up with a canted barrel.  I used the all-thread method to install the barrel, and it is straight enough that the RSB fits into the channel on the top of the trunion, but it is slightly canted such that the RSB touches the wall of the trunion channel on one side.  I am guessing that when I drive the barrel pin back in, that the force of the pin will twist the barrel the remaining degrees to a vertical position.  Any thoughts?  I think having to twist the receiver and barrel by any other method at this point is gonna be a trick.

How snug is the barrell in the trunion. If it went in failry
easily it might twist fro you. If not, you might have a
hard time getting the pin in. How does the pin hole look?

I just went through the pain of this exact issue, and while I'm definitely no expert, here's what worked for me:

Tap the barrel in a little farther than you need. Then, using the top edge of your vice, flip the  rifle so the barrel is now facing down and one of the corners of the trunnion is now resting on the vice. Using your brass nut or roll of pennies gently tap the barrel "out" while you twist the barrel in the direction you need to go. Tap gently, but twist as hard as you can. Once you are lined up, tap the barrel home in either direction. Remember to use an old slant brake or muzzle nut to protect your crown. Also, it may seem like you need four hands at first, but I used a little tape to hold in my brass punch so I could focus on twisting.

I knew I was completely lined up when I could run a cleaning rod against the bottom of the barrel pin hole without getting hung up.

I was very happy with the barrel pin was seated. It was a good feeling.

Thanks for the infor so far guys.  My gun is an AMD-65, and so far everything has been super snug.  The barrel pin hole is pretty straight, straight enough that if I dressed the end of the pin slightly, it could probably be forced in.  However, I like the sound of goloud's  suggestion, and will probably try that first.  My only concern is bending the receiver while I am twisting.  Any suggestions how to grip the thing while twisting would be great.  I have a big adjustable wrench that might be useful, unless using this method, the trunion/receiver can be turned by hand.

Yes, it moved pretty easily when I tapped/twisted it by hand. Just lay either the top right or top left section of the trunnion on the vise. Use a rag or rubber mat to keep from scratching the receiver. It doesn't take much tapping at all. You just want to give it enough movement to be able to rotate the barrel.

ETA:

I thought about leaving it also, but it probably would have created sighting issues as well as the possibility of the piston hanging up on the slightly turned gas block.