To block or not to block...that is the question

The best option is to have a good welding shop add a subframe between the spring hangers and the trailers frame. Square or rectangular tubing. While they are at it , it does not hurt to have tubes run side to side at the three spring hanger locations. The picture below is after a frame repair. It shows old subframe and new cross tubes and gussets at the hangers. Print it off and take it to the welding shop with you.

Chris