The Bridge truss shouldn't affect the vibration of the TWA since it's not actually attached to the back, but it can make placement more difficult.
I usually offset the TWA a bit to the side when I'm dealing with a bridge truss or bridge doctor.
I've even flipped the X-brace over and put the magnets on the top side to get a bit lower clearance, but getting the brace under it was still a bit tricky...
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My general starting place is the widest point of the lower bout along the centerline, then I'll start to work my way south towards the endpin until I find the sweet spot.
On my Jumbo Baritone, it's a bit different, the cone of the TWA is pretty much directly under the bridge. As long as it's not in the way when you play, I say go for it!
I've seen them offset to just about every position and you should be able to EQ it to sound good just about anywhere, but keep it in the lower bout for the most resonance.
Just make sure the cone isn't butted up directly against one of the back braces.
Also, ask yourself if it will get in the way when you're playing. If so, then that may not be an ideal position.