Propane torch will work but need to be careful not to burn/melt the pvc. Hold the flame back pretty far and move back and forth constantly. Go slow with the bending to ensure you don’t pinch the pvc, you want it to keep its tube shape
If you can use hangers to anchor it in the position you want, then relax the curve with a heat gun, that should take the pressure off overflow bulkheads or whatever else youre worried about.
I anchored this run first (was a little tough since I wanted a pretty tight s curve in two planes) then relaxed it with a heat gun as described. It worked so well I could actually see the clamps relax a little, so I tightened them up