I had to straighten a small warp in a pretty substantial chunk of resin; it was a foot long, solid, one piece, waterline hull and superstructure of an Italian battleship from Regia Marina. I immersed it with a carafe of water just below boiling from a regular drip coffee maker, and laid a wide heavy object on top of the smokestacks to press it straight. After the water cooled, the piece was straightened out and I couldn't see any damage at the pressure points.
I have never had to straighten an Anigrand resin piece except for fuselage halves that could be straightened by simply super gluing them together. You might want to experiment with a small easily scratch buildable part to see if it has any problems.